diff --git a/Emby.Drawing/ImageProcessor.cs b/Emby.Drawing/ImageProcessor.cs
index 8a2301d2d6..aa8a3d212a 100644
--- a/Emby.Drawing/ImageProcessor.cs
+++ b/Emby.Drawing/ImageProcessor.cs
@@ -352,8 +352,13 @@ namespace Emby.Drawing
         }
 
         /// <inheritdoc />
-        public string GetImageCacheTag(User user)
+        public string? GetImageCacheTag(User user)
         {
+            if (user.ProfileImage == null)
+            {
+                return null;
+            }
+
             return (user.ProfileImage.Path + user.ProfileImage.LastModified.Ticks).GetMD5()
                 .ToString("N", CultureInfo.InvariantCulture);
         }
diff --git a/Jellyfin.Api/Controllers/ImageController.cs b/Jellyfin.Api/Controllers/ImageController.cs
index a50d6e46bf..b016f24500 100644
--- a/Jellyfin.Api/Controllers/ImageController.cs
+++ b/Jellyfin.Api/Controllers/ImageController.cs
@@ -196,6 +196,11 @@ namespace Jellyfin.Api.Controllers
             }
 
             var user = _userManager.GetUserById(userId);
+            if (user?.ProfileImage == null)
+            {
+                return NoContent();
+            }
+
             try
             {
                 System.IO.File.Delete(user.ProfileImage.Path);
@@ -235,6 +240,11 @@ namespace Jellyfin.Api.Controllers
             }
 
             var user = _userManager.GetUserById(userId);
+            if (user?.ProfileImage == null)
+            {
+                return NoContent();
+            }
+
             try
             {
                 System.IO.File.Delete(user.ProfileImage.Path);
@@ -1469,7 +1479,7 @@ namespace Jellyfin.Api.Controllers
             [FromQuery] int? imageIndex)
         {
             var user = _userManager.GetUserById(userId);
-            if (user == null)
+            if (user?.ProfileImage == null)
             {
                 return NotFound();
             }
diff --git a/Jellyfin.Api/Controllers/StartupController.cs b/Jellyfin.Api/Controllers/StartupController.cs
index d9cb34557b..a01a617fc0 100644
--- a/Jellyfin.Api/Controllers/StartupController.cs
+++ b/Jellyfin.Api/Controllers/StartupController.cs
@@ -132,7 +132,10 @@ namespace Jellyfin.Api.Controllers
         {
             var user = _userManager.Users.First();
 
-            user.Username = startupUserDto.Name;
+            if (startupUserDto.Name != null)
+            {
+                user.Username = startupUserDto.Name;
+            }
 
             await _userManager.UpdateUserAsync(user).ConfigureAwait(false);
 
diff --git a/Jellyfin.Data/Entities/AccessSchedule.cs b/Jellyfin.Data/Entities/AccessSchedule.cs
index 72bca061da..9ac0666ac3 100644
--- a/Jellyfin.Data/Entities/AccessSchedule.cs
+++ b/Jellyfin.Data/Entities/AccessSchedule.cs
@@ -1,5 +1,4 @@
 using System;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 using System.Xml.Serialization;
 using Jellyfin.Data.Enums;
@@ -33,8 +32,6 @@ namespace Jellyfin.Data.Entities
         /// Identity, Indexed, Required.
         /// </remarks>
         [XmlIgnore]
-        [Key]
-        [Required]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
         public int Id { get; protected set; }
 
@@ -42,28 +39,24 @@ namespace Jellyfin.Data.Entities
         /// Gets or sets the id of the associated user.
         /// </summary>
         [XmlIgnore]
-        [Required]
         public Guid UserId { get; protected set; }
 
         /// <summary>
         /// Gets or sets the day of week.
         /// </summary>
         /// <value>The day of week.</value>
-        [Required]
         public DynamicDayOfWeek DayOfWeek { get; set; }
 
         /// <summary>
         /// Gets or sets the start hour.
         /// </summary>
         /// <value>The start hour.</value>
-        [Required]
         public double StartHour { get; set; }
 
         /// <summary>
         /// Gets or sets the end hour.
         /// </summary>
         /// <value>The end hour.</value>
-        [Required]
         public double EndHour { get; set; }
 
         /// <summary>
diff --git a/Jellyfin.Data/Entities/ActivityLog.cs b/Jellyfin.Data/Entities/ActivityLog.cs
index 80e32db30e..e4534e8b5e 100644
--- a/Jellyfin.Data/Entities/ActivityLog.cs
+++ b/Jellyfin.Data/Entities/ActivityLog.cs
@@ -50,7 +50,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required, Max length = 512.
         /// </remarks>
-        [Required]
         [MaxLength(512)]
         [StringLength(512)]
         public string Name { get; set; }
@@ -63,7 +62,7 @@ namespace Jellyfin.Data.Entities
         /// </remarks>
         [MaxLength(512)]
         [StringLength(512)]
-        public string Overview { get; set; }
+        public string? Overview { get; set; }
 
         /// <summary>
         /// Gets or sets the short overview.
@@ -73,7 +72,7 @@ namespace Jellyfin.Data.Entities
         /// </remarks>
         [MaxLength(512)]
         [StringLength(512)]
-        public string ShortOverview { get; set; }
+        public string? ShortOverview { get; set; }
 
         /// <summary>
         /// Gets or sets the type.
@@ -81,7 +80,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required, Max length = 256.
         /// </remarks>
-        [Required]
         [MaxLength(256)]
         [StringLength(256)]
         public string Type { get; set; }
@@ -102,7 +100,7 @@ namespace Jellyfin.Data.Entities
         /// </remarks>
         [MaxLength(256)]
         [StringLength(256)]
-        public string ItemId { get; set; }
+        public string? ItemId { get; set; }
 
         /// <summary>
         /// Gets or sets the date created. This should be in UTC.
diff --git a/Jellyfin.Data/Entities/CustomItemDisplayPreferences.cs b/Jellyfin.Data/Entities/CustomItemDisplayPreferences.cs
index d407180d46..cc46248c75 100644
--- a/Jellyfin.Data/Entities/CustomItemDisplayPreferences.cs
+++ b/Jellyfin.Data/Entities/CustomItemDisplayPreferences.cs
@@ -57,7 +57,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required. Max Length = 32.
         /// </remarks>
-        [Required]
         [MaxLength(32)]
         [StringLength(32)]
         public string Client { get; set; }
@@ -68,7 +67,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required.
         /// </remarks>
-        [Required]
         public string Key { get; set; }
 
         /// <summary>
@@ -77,7 +75,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required.
         /// </remarks>
-        [Required]
         public string Value { get; set; }
     }
 }
diff --git a/Jellyfin.Data/Entities/DisplayPreferences.cs b/Jellyfin.Data/Entities/DisplayPreferences.cs
index d186deb293..64cd6812a4 100644
--- a/Jellyfin.Data/Entities/DisplayPreferences.cs
+++ b/Jellyfin.Data/Entities/DisplayPreferences.cs
@@ -30,8 +30,6 @@ namespace Jellyfin.Data.Entities
             SkipBackwardLength = 10000;
             ScrollDirection = ScrollDirection.Horizontal;
             ChromecastVersion = ChromecastVersion.Stable;
-            DashboardTheme = string.Empty;
-            TvHome = string.Empty;
 
             HomeSections = new HashSet<HomeSection>();
         }
@@ -67,7 +65,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required. Max Length = 32.
         /// </remarks>
-        [Required]
         [MaxLength(32)]
         [StringLength(32)]
         public string Client { get; set; }
@@ -138,14 +135,14 @@ namespace Jellyfin.Data.Entities
         /// </summary>
         [MaxLength(32)]
         [StringLength(32)]
-        public string DashboardTheme { get; set; }
+        public string? DashboardTheme { get; set; }
 
         /// <summary>
         /// Gets or sets the tv home screen.
         /// </summary>
         [MaxLength(32)]
         [StringLength(32)]
-        public string TvHome { get; set; }
+        public string? TvHome { get; set; }
 
         /// <summary>
         /// Gets or sets the home sections.
diff --git a/Jellyfin.Data/Entities/Group.cs b/Jellyfin.Data/Entities/Group.cs
index 8c45dde928..b14e22b7b3 100644
--- a/Jellyfin.Data/Entities/Group.cs
+++ b/Jellyfin.Data/Entities/Group.cs
@@ -46,7 +46,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required, Max length = 255.
         /// </remarks>
-        [Required]
         [MaxLength(255)]
         [StringLength(255)]
         public string Name { get; set; }
diff --git a/Jellyfin.Data/Entities/HomeSection.cs b/Jellyfin.Data/Entities/HomeSection.cs
index 0620462602..5adc52491c 100644
--- a/Jellyfin.Data/Entities/HomeSection.cs
+++ b/Jellyfin.Data/Entities/HomeSection.cs
@@ -15,7 +15,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Identity. Required.
         /// </remarks>
-        [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
         public int Id { get; protected set; }
 
diff --git a/Jellyfin.Data/Entities/ImageInfo.cs b/Jellyfin.Data/Entities/ImageInfo.cs
index f9ae1a955f..e0c37047d8 100644
--- a/Jellyfin.Data/Entities/ImageInfo.cs
+++ b/Jellyfin.Data/Entities/ImageInfo.cs
@@ -39,7 +39,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required.
         /// </remarks>
-        [Required]
         [MaxLength(512)]
         [StringLength(512)]
         public string Path { get; set; }
diff --git a/Jellyfin.Data/Entities/ItemDisplayPreferences.cs b/Jellyfin.Data/Entities/ItemDisplayPreferences.cs
index f0a04f8ea6..4bfeb2fa30 100644
--- a/Jellyfin.Data/Entities/ItemDisplayPreferences.cs
+++ b/Jellyfin.Data/Entities/ItemDisplayPreferences.cs
@@ -59,7 +59,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required. Max Length = 32.
         /// </remarks>
-        [Required]
         [MaxLength(32)]
         [StringLength(32)]
         public string Client { get; set; }
@@ -99,7 +98,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required.
         /// </remarks>
-        [Required]
         [MaxLength(64)]
         [StringLength(64)]
         public string SortBy { get; set; }
diff --git a/Jellyfin.Data/Entities/Libraries/Artwork.cs b/Jellyfin.Data/Entities/Libraries/Artwork.cs
index df28ce7374..84a524de2c 100644
--- a/Jellyfin.Data/Entities/Libraries/Artwork.cs
+++ b/Jellyfin.Data/Entities/Libraries/Artwork.cs
@@ -44,7 +44,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// Required, Max length = 65535.
         /// </remarks>
-        [Required]
         [MaxLength(65535)]
         [StringLength(65535)]
         public string Path { get; set; }
diff --git a/Jellyfin.Data/Entities/Libraries/BookMetadata.cs b/Jellyfin.Data/Entities/Libraries/BookMetadata.cs
index 8b0c965306..1ff4327b01 100644
--- a/Jellyfin.Data/Entities/Libraries/BookMetadata.cs
+++ b/Jellyfin.Data/Entities/Libraries/BookMetadata.cs
@@ -1,7 +1,6 @@
 #pragma warning disable CA2227
 
 using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations.Schema;
 using Jellyfin.Data.Interfaces;
 
 namespace Jellyfin.Data.Entities.Libraries
@@ -32,7 +31,6 @@ namespace Jellyfin.Data.Entities.Libraries
         public virtual ICollection<Company> Publishers { get; protected set; }
 
         /// <inheritdoc />
-        [NotMapped]
         public ICollection<Company> Companies => Publishers;
     }
 }
diff --git a/Jellyfin.Data/Entities/Libraries/Chapter.cs b/Jellyfin.Data/Entities/Libraries/Chapter.cs
index f253143d74..11f53ae20a 100644
--- a/Jellyfin.Data/Entities/Libraries/Chapter.cs
+++ b/Jellyfin.Data/Entities/Libraries/Chapter.cs
@@ -45,7 +45,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         /// <summary>
         /// Gets or sets the language.
@@ -54,7 +54,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// Required, Min length = 3, Max length = 3
         /// ISO-639-3 3-character language codes.
         /// </remarks>
-        [Required]
         [MinLength(3)]
         [MaxLength(3)]
         [StringLength(3)]
diff --git a/Jellyfin.Data/Entities/Libraries/Collection.cs b/Jellyfin.Data/Entities/Libraries/Collection.cs
index 39eded752d..d230eeb2fe 100644
--- a/Jellyfin.Data/Entities/Libraries/Collection.cs
+++ b/Jellyfin.Data/Entities/Libraries/Collection.cs
@@ -37,7 +37,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         /// <inheritdoc />
         [ConcurrencyCheck]
diff --git a/Jellyfin.Data/Entities/Libraries/CollectionItem.cs b/Jellyfin.Data/Entities/Libraries/CollectionItem.cs
index 1157de442b..e19362bdf1 100644
--- a/Jellyfin.Data/Entities/Libraries/CollectionItem.cs
+++ b/Jellyfin.Data/Entities/Libraries/CollectionItem.cs
@@ -9,6 +9,15 @@ namespace Jellyfin.Data.Entities.Libraries
     /// </summary>
     public class CollectionItem : IHasConcurrencyToken
     {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CollectionItem"/> class.
+        /// </summary>
+        /// <param name="libraryItem">The library item.</param>
+        public CollectionItem(LibraryItem libraryItem)
+        {
+            LibraryItem = libraryItem;
+        }
+
         /// <summary>
         /// Gets or sets the id.
         /// </summary>
@@ -36,7 +45,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// TODO check if this properly updated Dependant and has the proper principal relationship.
         /// </remarks>
-        public virtual CollectionItem Next { get; set; }
+        public virtual CollectionItem? Next { get; set; }
 
         /// <summary>
         /// Gets or sets the previous item in the collection.
@@ -44,7 +53,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// TODO check if this properly updated Dependant and has the proper principal relationship.
         /// </remarks>
-        public virtual CollectionItem Previous { get; set; }
+        public virtual CollectionItem? Previous { get; set; }
 
         /// <inheritdoc />
         public void OnSavingChanges()
diff --git a/Jellyfin.Data/Entities/Libraries/Company.cs b/Jellyfin.Data/Entities/Libraries/Company.cs
index 499ba3800a..09050bb522 100644
--- a/Jellyfin.Data/Entities/Libraries/Company.cs
+++ b/Jellyfin.Data/Entities/Libraries/Company.cs
@@ -18,6 +18,7 @@ namespace Jellyfin.Data.Entities.Libraries
         public Company()
         {
             CompanyMetadata = new HashSet<CompanyMetadata>();
+            ChildCompanies = new HashSet<Company>();
         }
 
         /// <summary>
@@ -44,7 +45,6 @@ namespace Jellyfin.Data.Entities.Libraries
         public virtual ICollection<Company> ChildCompanies { get; protected set; }
 
         /// <inheritdoc />
-        [NotMapped]
         public ICollection<Company> Companies => ChildCompanies;
 
         /// <inheritdoc />
diff --git a/Jellyfin.Data/Entities/Libraries/CompanyMetadata.cs b/Jellyfin.Data/Entities/Libraries/CompanyMetadata.cs
index 86642b38a5..a29f08c7f6 100644
--- a/Jellyfin.Data/Entities/Libraries/CompanyMetadata.cs
+++ b/Jellyfin.Data/Entities/Libraries/CompanyMetadata.cs
@@ -24,7 +24,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(65535)]
         [StringLength(65535)]
-        public string Description { get; set; }
+        public string? Description { get; set; }
 
         /// <summary>
         /// Gets or sets the headquarters.
@@ -34,7 +34,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(255)]
         [StringLength(255)]
-        public string Headquarters { get; set; }
+        public string? Headquarters { get; set; }
 
         /// <summary>
         /// Gets or sets the country code.
@@ -44,7 +44,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(2)]
         [StringLength(2)]
-        public string Country { get; set; }
+        public string? Country { get; set; }
 
         /// <summary>
         /// Gets or sets the homepage.
@@ -54,6 +54,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string Homepage { get; set; }
+        public string? Homepage { get; set; }
     }
 }
diff --git a/Jellyfin.Data/Entities/Libraries/CustomItemMetadata.cs b/Jellyfin.Data/Entities/Libraries/CustomItemMetadata.cs
index a69a8eafa4..af2393870f 100644
--- a/Jellyfin.Data/Entities/Libraries/CustomItemMetadata.cs
+++ b/Jellyfin.Data/Entities/Libraries/CustomItemMetadata.cs
@@ -1,5 +1,3 @@
-using System;
-
 namespace Jellyfin.Data.Entities.Libraries
 {
     /// <summary>
diff --git a/Jellyfin.Data/Entities/Libraries/EpisodeMetadata.cs b/Jellyfin.Data/Entities/Libraries/EpisodeMetadata.cs
index 5662decdb8..b0ef11e0f2 100644
--- a/Jellyfin.Data/Entities/Libraries/EpisodeMetadata.cs
+++ b/Jellyfin.Data/Entities/Libraries/EpisodeMetadata.cs
@@ -24,7 +24,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string Outline { get; set; }
+        public string? Outline { get; set; }
 
         /// <summary>
         /// Gets or sets the plot.
@@ -34,7 +34,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(65535)]
         [StringLength(65535)]
-        public string Plot { get; set; }
+        public string? Plot { get; set; }
 
         /// <summary>
         /// Gets or sets the tagline.
@@ -44,6 +44,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string Tagline { get; set; }
+        public string? Tagline { get; set; }
     }
 }
diff --git a/Jellyfin.Data/Entities/Libraries/Genre.cs b/Jellyfin.Data/Entities/Libraries/Genre.cs
index befa75550a..9f3d650283 100644
--- a/Jellyfin.Data/Entities/Libraries/Genre.cs
+++ b/Jellyfin.Data/Entities/Libraries/Genre.cs
@@ -33,7 +33,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// Indexed, Required, Max length = 255.
         /// </remarks>
-        [Required]
         [MaxLength(255)]
         [StringLength(255)]
         public string Name { get; set; }
diff --git a/Jellyfin.Data/Entities/Libraries/ItemMetadata.cs b/Jellyfin.Data/Entities/Libraries/ItemMetadata.cs
index a0efa66e46..d12e011a8b 100644
--- a/Jellyfin.Data/Entities/Libraries/ItemMetadata.cs
+++ b/Jellyfin.Data/Entities/Libraries/ItemMetadata.cs
@@ -57,7 +57,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// Required, Max length = 1024.
         /// </remarks>
-        [Required]
         [MaxLength(1024)]
         [StringLength(1024)]
         public string Title { get; set; }
@@ -70,7 +69,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string OriginalTitle { get; set; }
+        public string? OriginalTitle { get; set; }
 
         /// <summary>
         /// Gets or sets the sort title.
@@ -80,7 +79,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string SortTitle { get; set; }
+        public string? SortTitle { get; set; }
 
         /// <summary>
         /// Gets or sets the language.
@@ -89,7 +88,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// Required, Min length = 3, Max length = 3.
         /// ISO-639-3 3-character language codes.
         /// </remarks>
-        [Required]
         [MinLength(3)]
         [MaxLength(3)]
         [StringLength(3)]
diff --git a/Jellyfin.Data/Entities/Libraries/Library.cs b/Jellyfin.Data/Entities/Libraries/Library.cs
index 3ec4341a48..e453849020 100644
--- a/Jellyfin.Data/Entities/Libraries/Library.cs
+++ b/Jellyfin.Data/Entities/Libraries/Library.cs
@@ -1,4 +1,3 @@
-using System;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 using Jellyfin.Data.Interfaces;
@@ -14,14 +13,11 @@ namespace Jellyfin.Data.Entities.Libraries
         /// Initializes a new instance of the <see cref="Library"/> class.
         /// </summary>
         /// <param name="name">The name of the library.</param>
-        public Library(string name)
+        /// <param name="path">The path of the library.</param>
+        public Library(string name, string path)
         {
-            if (string.IsNullOrWhiteSpace(name))
-            {
-                throw new ArgumentNullException(nameof(name));
-            }
-
             Name = name;
+            Path = path;
         }
 
         /// <summary>
@@ -39,7 +35,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// Required, Max length = 128.
         /// </remarks>
-        [Required]
         [MaxLength(128)]
         [StringLength(128)]
         public string Name { get; set; }
@@ -50,7 +45,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// Required.
         /// </remarks>
-        [Required]
         public string Path { get; set; }
 
         /// <inheritdoc />
diff --git a/Jellyfin.Data/Entities/Libraries/LibraryItem.cs b/Jellyfin.Data/Entities/Libraries/LibraryItem.cs
index 504b9c853b..67ffad944b 100644
--- a/Jellyfin.Data/Entities/Libraries/LibraryItem.cs
+++ b/Jellyfin.Data/Entities/Libraries/LibraryItem.cs
@@ -44,7 +44,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// Required.
         /// </remarks>
-        [Required]
         public virtual Library Library { get; set; }
 
         /// <inheritdoc />
diff --git a/Jellyfin.Data/Entities/Libraries/MediaFile.cs b/Jellyfin.Data/Entities/Libraries/MediaFile.cs
index 7f64978e24..f3e2fe6539 100644
--- a/Jellyfin.Data/Entities/Libraries/MediaFile.cs
+++ b/Jellyfin.Data/Entities/Libraries/MediaFile.cs
@@ -47,7 +47,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// Required, Max length = 65535.
         /// </remarks>
-        [Required]
         [MaxLength(65535)]
         [StringLength(65535)]
         public string Path { get; set; }
diff --git a/Jellyfin.Data/Entities/Libraries/MetadataProvider.cs b/Jellyfin.Data/Entities/Libraries/MetadataProvider.cs
index 20de5bf4bb..fb2587882d 100644
--- a/Jellyfin.Data/Entities/Libraries/MetadataProvider.cs
+++ b/Jellyfin.Data/Entities/Libraries/MetadataProvider.cs
@@ -39,7 +39,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// Required, Max length = 1024.
         /// </remarks>
-        [Required]
         [MaxLength(1024)]
         [StringLength(1024)]
         public string Name { get; set; }
diff --git a/Jellyfin.Data/Entities/Libraries/MetadataProviderId.cs b/Jellyfin.Data/Entities/Libraries/MetadataProviderId.cs
index 12672dd25b..2a9c904c88 100644
--- a/Jellyfin.Data/Entities/Libraries/MetadataProviderId.cs
+++ b/Jellyfin.Data/Entities/Libraries/MetadataProviderId.cs
@@ -14,7 +14,8 @@ namespace Jellyfin.Data.Entities.Libraries
         /// Initializes a new instance of the <see cref="MetadataProviderId"/> class.
         /// </summary>
         /// <param name="providerId">The provider id.</param>
-        public MetadataProviderId(string providerId)
+        /// <param name="metadataProvider">The metadata provider.</param>
+        public MetadataProviderId(string providerId, MetadataProvider metadataProvider)
         {
             if (string.IsNullOrEmpty(providerId))
             {
@@ -22,6 +23,7 @@ namespace Jellyfin.Data.Entities.Libraries
             }
 
             ProviderId = providerId;
+            MetadataProvider = metadataProvider;
         }
 
         /// <summary>
@@ -39,7 +41,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// Required, Max length = 255.
         /// </remarks>
-        [Required]
         [MaxLength(255)]
         [StringLength(255)]
         public string ProviderId { get; set; }
diff --git a/Jellyfin.Data/Entities/Libraries/MovieMetadata.cs b/Jellyfin.Data/Entities/Libraries/MovieMetadata.cs
index 8cf7ca6a7f..fb181dea60 100644
--- a/Jellyfin.Data/Entities/Libraries/MovieMetadata.cs
+++ b/Jellyfin.Data/Entities/Libraries/MovieMetadata.cs
@@ -2,7 +2,6 @@
 
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations.Schema;
 using Jellyfin.Data.Interfaces;
 
 namespace Jellyfin.Data.Entities.Libraries
@@ -30,7 +29,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string Outline { get; set; }
+        public string? Outline { get; set; }
 
         /// <summary>
         /// Gets or sets the tagline.
@@ -40,7 +39,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string Tagline { get; set; }
+        public string? Tagline { get; set; }
 
         /// <summary>
         /// Gets or sets the plot.
@@ -50,7 +49,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(65535)]
         [StringLength(65535)]
-        public string Plot { get; set; }
+        public string? Plot { get; set; }
 
         /// <summary>
         /// Gets or sets the country code.
@@ -60,7 +59,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(2)]
         [StringLength(2)]
-        public string Country { get; set; }
+        public string? Country { get; set; }
 
         /// <summary>
         /// Gets or sets the studios that produced this movie.
@@ -68,7 +67,6 @@ namespace Jellyfin.Data.Entities.Libraries
         public virtual ICollection<Company> Studios { get; protected set; }
 
         /// <inheritdoc />
-        [NotMapped]
         public ICollection<Company> Companies => Studios;
     }
 }
diff --git a/Jellyfin.Data/Entities/Libraries/MusicAlbumMetadata.cs b/Jellyfin.Data/Entities/Libraries/MusicAlbumMetadata.cs
index 9e44e550af..3080bd692d 100644
--- a/Jellyfin.Data/Entities/Libraries/MusicAlbumMetadata.cs
+++ b/Jellyfin.Data/Entities/Libraries/MusicAlbumMetadata.cs
@@ -28,7 +28,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(255)]
         [StringLength(255)]
-        public string Barcode { get; set; }
+        public string? Barcode { get; set; }
 
         /// <summary>
         /// Gets or sets the label number.
@@ -38,7 +38,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(255)]
         [StringLength(255)]
-        public string LabelNumber { get; set; }
+        public string? LabelNumber { get; set; }
 
         /// <summary>
         /// Gets or sets the country code.
@@ -48,7 +48,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(2)]
         [StringLength(2)]
-        public string Country { get; set; }
+        public string? Country { get; set; }
 
         /// <summary>
         /// Gets or sets a collection containing the labels.
diff --git a/Jellyfin.Data/Entities/Libraries/Person.cs b/Jellyfin.Data/Entities/Libraries/Person.cs
index cc4b9e0f9f..159bd47be7 100644
--- a/Jellyfin.Data/Entities/Libraries/Person.cs
+++ b/Jellyfin.Data/Entities/Libraries/Person.cs
@@ -46,7 +46,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// Required, Max length = 1024.
         /// </remarks>
-        [Required]
         [MaxLength(1024)]
         [StringLength(1024)]
         public string Name { get; set; }
@@ -59,7 +58,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(256)]
         [StringLength(256)]
-        public string SourceId { get; set; }
+        public string? SourceId { get; set; }
 
         /// <summary>
         /// Gets or sets the date added.
diff --git a/Jellyfin.Data/Entities/Libraries/PersonRole.cs b/Jellyfin.Data/Entities/Libraries/PersonRole.cs
index 3ae2e4a685..988aa84bae 100644
--- a/Jellyfin.Data/Entities/Libraries/PersonRole.cs
+++ b/Jellyfin.Data/Entities/Libraries/PersonRole.cs
@@ -17,9 +17,12 @@ namespace Jellyfin.Data.Entities.Libraries
         /// Initializes a new instance of the <see cref="PersonRole"/> class.
         /// </summary>
         /// <param name="type">The role type.</param>
-        public PersonRole(PersonRoleType type)
+        /// <param name="person">The person.</param>
+        public PersonRole(PersonRoleType type, Person person)
         {
             Type = type;
+            Person = person;
+            Artwork = new HashSet<Artwork>();
             Sources = new HashSet<MetadataProviderId>();
         }
 
@@ -40,7 +43,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string Role { get; set; }
+        public string? Role { get; set; }
 
         /// <summary>
         /// Gets or sets the person's role type.
@@ -60,7 +63,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// Required.
         /// </remarks>
-        [Required]
         public virtual Person Person { get; set; }
 
         /// <inheritdoc />
diff --git a/Jellyfin.Data/Entities/Libraries/Rating.cs b/Jellyfin.Data/Entities/Libraries/Rating.cs
index 0ea933fd79..6862012a80 100644
--- a/Jellyfin.Data/Entities/Libraries/Rating.cs
+++ b/Jellyfin.Data/Entities/Libraries/Rating.cs
@@ -48,7 +48,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// Gets or sets the rating type.
         /// If this is <c>null</c> it's the internal user rating.
         /// </summary>
-        public virtual RatingSource RatingType { get; set; }
+        public virtual RatingSource? RatingType { get; set; }
 
         /// <inheritdoc />
         public void OnSavingChanges()
diff --git a/Jellyfin.Data/Entities/Libraries/RatingSource.cs b/Jellyfin.Data/Entities/Libraries/RatingSource.cs
index 7e1a5a8f46..ae0d806ff0 100644
--- a/Jellyfin.Data/Entities/Libraries/RatingSource.cs
+++ b/Jellyfin.Data/Entities/Libraries/RatingSource.cs
@@ -37,7 +37,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         /// <summary>
         /// Gets or sets the minimum value.
@@ -62,7 +62,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <summary>
         /// Gets or sets the metadata source.
         /// </summary>
-        public virtual MetadataProviderId Source { get; set; }
+        public virtual MetadataProviderId? Source { get; set; }
 
         /// <inheritdoc />
         public void OnSavingChanges()
diff --git a/Jellyfin.Data/Entities/Libraries/Release.cs b/Jellyfin.Data/Entities/Libraries/Release.cs
index 1871e0f10b..21d4039793 100644
--- a/Jellyfin.Data/Entities/Libraries/Release.cs
+++ b/Jellyfin.Data/Entities/Libraries/Release.cs
@@ -45,7 +45,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// <remarks>
         /// Required, Max length = 1024.
         /// </remarks>
-        [Required]
         [MaxLength(1024)]
         [StringLength(1024)]
         public string Name { get; set; }
diff --git a/Jellyfin.Data/Entities/Libraries/SeasonMetadata.cs b/Jellyfin.Data/Entities/Libraries/SeasonMetadata.cs
index 61714f9095..da40a075f5 100644
--- a/Jellyfin.Data/Entities/Libraries/SeasonMetadata.cs
+++ b/Jellyfin.Data/Entities/Libraries/SeasonMetadata.cs
@@ -24,6 +24,6 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string Outline { get; set; }
+        public string? Outline { get; set; }
     }
 }
diff --git a/Jellyfin.Data/Entities/Libraries/SeriesMetadata.cs b/Jellyfin.Data/Entities/Libraries/SeriesMetadata.cs
index e1acd2d457..730deccaed 100644
--- a/Jellyfin.Data/Entities/Libraries/SeriesMetadata.cs
+++ b/Jellyfin.Data/Entities/Libraries/SeriesMetadata.cs
@@ -30,7 +30,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string Outline { get; set; }
+        public string? Outline { get; set; }
 
         /// <summary>
         /// Gets or sets the plot.
@@ -40,7 +40,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(65535)]
         [StringLength(65535)]
-        public string Plot { get; set; }
+        public string? Plot { get; set; }
 
         /// <summary>
         /// Gets or sets the tagline.
@@ -50,7 +50,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(1024)]
         [StringLength(1024)]
-        public string Tagline { get; set; }
+        public string? Tagline { get; set; }
 
         /// <summary>
         /// Gets or sets the country code.
@@ -60,7 +60,7 @@ namespace Jellyfin.Data.Entities.Libraries
         /// </remarks>
         [MaxLength(2)]
         [StringLength(2)]
-        public string Country { get; set; }
+        public string? Country { get; set; }
 
         /// <summary>
         /// Gets or sets a collection containing the networks.
@@ -68,7 +68,6 @@ namespace Jellyfin.Data.Entities.Libraries
         public virtual ICollection<Company> Networks { get; protected set; }
 
         /// <inheritdoc />
-        [NotMapped]
         public ICollection<Company> Companies => Networks;
     }
 }
diff --git a/Jellyfin.Data/Entities/Preference.cs b/Jellyfin.Data/Entities/Preference.cs
index 40f2f8ede9..a8813ab88d 100644
--- a/Jellyfin.Data/Entities/Preference.cs
+++ b/Jellyfin.Data/Entities/Preference.cs
@@ -46,7 +46,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required, Max length = 65535.
         /// </remarks>
-        [Required]
         [MaxLength(65535)]
         [StringLength(65535)]
         public string Value { get; set; }
diff --git a/Jellyfin.Data/Entities/User.cs b/Jellyfin.Data/Entities/User.cs
index 28e12adde6..9aa8091640 100644
--- a/Jellyfin.Data/Entities/User.cs
+++ b/Jellyfin.Data/Entities/User.cs
@@ -51,6 +51,7 @@ namespace Jellyfin.Data.Entities
             PasswordResetProviderId = passwordResetProviderId;
 
             AccessSchedules = new HashSet<AccessSchedule>();
+            DisplayPreferences = new HashSet<DisplayPreferences>();
             ItemDisplayPreferences = new HashSet<ItemDisplayPreferences>();
             // Groups = new HashSet<Group>();
             Permissions = new HashSet<Permission>();
@@ -92,7 +93,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required, Max length = 255.
         /// </remarks>
-        [Required]
         [MaxLength(255)]
         [StringLength(255)]
         public string Username { get; set; }
@@ -105,7 +105,7 @@ namespace Jellyfin.Data.Entities
         /// </remarks>
         [MaxLength(65535)]
         [StringLength(65535)]
-        public string Password { get; set; }
+        public string? Password { get; set; }
 
         /// <summary>
         /// Gets or sets the user's easy password, or <c>null</c> if none is set.
@@ -115,7 +115,7 @@ namespace Jellyfin.Data.Entities
         /// </remarks>
         [MaxLength(65535)]
         [StringLength(65535)]
-        public string EasyPassword { get; set; }
+        public string? EasyPassword { get; set; }
 
         /// <summary>
         /// Gets or sets a value indicating whether the user must update their password.
@@ -133,7 +133,7 @@ namespace Jellyfin.Data.Entities
         /// </remarks>
         [MaxLength(255)]
         [StringLength(255)]
-        public string AudioLanguagePreference { get; set; }
+        public string? AudioLanguagePreference { get; set; }
 
         /// <summary>
         /// Gets or sets the authentication provider id.
@@ -141,7 +141,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required, Max length = 255.
         /// </remarks>
-        [Required]
         [MaxLength(255)]
         [StringLength(255)]
         public string AuthenticationProviderId { get; set; }
@@ -152,7 +151,6 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required, Max length = 255.
         /// </remarks>
-        [Required]
         [MaxLength(255)]
         [StringLength(255)]
         public string PasswordResetProviderId { get; set; }
@@ -209,7 +207,7 @@ namespace Jellyfin.Data.Entities
         /// </remarks>
         [MaxLength(255)]
         [StringLength(255)]
-        public string SubtitleLanguagePreference { get; set; }
+        public string? SubtitleLanguagePreference { get; set; }
 
         /// <summary>
         /// Gets or sets a value indicating whether missing episodes should be displayed.
@@ -304,7 +302,7 @@ namespace Jellyfin.Data.Entities
         /// Gets or sets the user's profile image. Can be <c>null</c>.
         /// </summary>
         // [ForeignKey("UserId")]
-        public virtual ImageInfo ProfileImage { get; set; }
+        public virtual ImageInfo? ProfileImage { get; set; }
 
         /// <summary>
         /// Gets or sets the user's display preferences.
@@ -312,8 +310,7 @@ namespace Jellyfin.Data.Entities
         /// <remarks>
         /// Required.
         /// </remarks>
-        [Required]
-        public virtual DisplayPreferences DisplayPreferences { get; set; }
+        public virtual ICollection<DisplayPreferences> DisplayPreferences { get; set; }
 
         /// <summary>
         /// Gets or sets the level of sync play permissions this user has.
diff --git a/Jellyfin.Data/Jellyfin.Data.csproj b/Jellyfin.Data/Jellyfin.Data.csproj
index a8ac45645f..a2b6f074e4 100644
--- a/Jellyfin.Data/Jellyfin.Data.csproj
+++ b/Jellyfin.Data/Jellyfin.Data.csproj
@@ -5,6 +5,7 @@
     <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    <Nullable>enable</Nullable>
     <PublishRepositoryUrl>true</PublishRepositoryUrl>
     <EmbedUntrackedSources>true</EmbedUntrackedSources>
     <IncludeSymbols>true</IncludeSymbols>
diff --git a/Jellyfin.Server.Implementations/Events/Consumers/Session/PlaybackStartLogger.cs b/Jellyfin.Server.Implementations/Events/Consumers/Session/PlaybackStartLogger.cs
index 0340248bbd..aa6015caae 100644
--- a/Jellyfin.Server.Implementations/Events/Consumers/Session/PlaybackStartLogger.cs
+++ b/Jellyfin.Server.Implementations/Events/Consumers/Session/PlaybackStartLogger.cs
@@ -86,7 +86,7 @@ namespace Jellyfin.Server.Implementations.Events.Consumers.Session
             return name;
         }
 
-        private static string? GetPlaybackNotificationType(string mediaType)
+        private static string GetPlaybackNotificationType(string mediaType)
         {
             if (string.Equals(mediaType, MediaType.Audio, StringComparison.OrdinalIgnoreCase))
             {
@@ -98,7 +98,7 @@ namespace Jellyfin.Server.Implementations.Events.Consumers.Session
                 return NotificationType.VideoPlayback.ToString();
             }
 
-            return null;
+            return "Playback";
         }
     }
 }
diff --git a/Jellyfin.Server.Implementations/Users/UserManager.cs b/Jellyfin.Server.Implementations/Users/UserManager.cs
index 76d1389caf..b400a0dd1b 100644
--- a/Jellyfin.Server.Implementations/Users/UserManager.cs
+++ b/Jellyfin.Server.Implementations/Users/UserManager.cs
@@ -184,8 +184,8 @@ namespace Jellyfin.Server.Implementations.Users
 
             var user = new User(
                 name,
-                _defaultAuthenticationProvider.GetType().FullName,
-                _defaultPasswordResetProvider.GetType().FullName)
+                _defaultAuthenticationProvider.GetType().FullName!,
+                _defaultPasswordResetProvider.GetType().FullName!)
             {
                 InternalId = max + 1
             };
@@ -444,7 +444,7 @@ namespace Jellyfin.Server.Implementations.Users
             {
                 var providerId = authenticationProvider.GetType().FullName;
 
-                if (!string.Equals(providerId, user.AuthenticationProviderId, StringComparison.OrdinalIgnoreCase))
+                if (providerId != null && !string.Equals(providerId, user.AuthenticationProviderId, StringComparison.OrdinalIgnoreCase))
                 {
                     user.AuthenticationProviderId = providerId;
                     await UpdateUserAsync(user).ConfigureAwait(false);
diff --git a/Jellyfin.Server/Migrations/Routines/MigrateUserDb.cs b/Jellyfin.Server/Migrations/Routines/MigrateUserDb.cs
index 33f039c394..6d318d2329 100644
--- a/Jellyfin.Server/Migrations/Routines/MigrateUserDb.cs
+++ b/Jellyfin.Server/Migrations/Routines/MigrateUserDb.cs
@@ -1,7 +1,5 @@
 using System;
-using System.Globalization;
 using System.IO;
-using System.Linq;
 using Emby.Server.Implementations.Data;
 using Emby.Server.Implementations.Serialization;
 using Jellyfin.Data.Entities;
@@ -104,7 +102,7 @@ namespace Jellyfin.Server.Migrations.Routines
                         _ => policy.LoginAttemptsBeforeLockout
                     };
 
-                    var user = new User(mockup.Name, policy.AuthenticationProviderId, policy.PasswordResetProviderId)
+                    var user = new User(mockup.Name, policy.AuthenticationProviderId!, policy.PasswordResetProviderId!)
                     {
                         Id = entry[1].ReadGuidFromBlob(),
                         InternalId = entry[0].ToInt64(),
diff --git a/MediaBrowser.Controller/Drawing/IImageProcessor.cs b/MediaBrowser.Controller/Drawing/IImageProcessor.cs
index 935a790312..142cebd0c0 100644
--- a/MediaBrowser.Controller/Drawing/IImageProcessor.cs
+++ b/MediaBrowser.Controller/Drawing/IImageProcessor.cs
@@ -61,7 +61,7 @@ namespace MediaBrowser.Controller.Drawing
 
         string GetImageCacheTag(BaseItem item, ChapterInfo info);
 
-        string GetImageCacheTag(User user);
+        string? GetImageCacheTag(User user);
 
         /// <summary>
         /// Processes the image.
diff --git a/tests/Jellyfin.Api.Tests/TestHelpers.cs b/tests/Jellyfin.Api.Tests/TestHelpers.cs
index f27cdf7b63..c1549561db 100644
--- a/tests/Jellyfin.Api.Tests/TestHelpers.cs
+++ b/tests/Jellyfin.Api.Tests/TestHelpers.cs
@@ -26,8 +26,8 @@ namespace Jellyfin.Api.Tests
         {
             var user = new User(
                 "jellyfin",
-                typeof(DefaultAuthenticationProvider).FullName,
-                typeof(DefaultPasswordResetProvider).FullName);
+                typeof(DefaultAuthenticationProvider).FullName!,
+                typeof(DefaultPasswordResetProvider).FullName!);
 
             // Set administrator flag.
             user.SetPermission(PermissionKind.IsAdministrator, role.Equals(UserRoles.Administrator, StringComparison.OrdinalIgnoreCase));