diff --git a/AsbCloudApp/Services/IUserSettingsRepository.cs b/AsbCloudApp/Services/IUserSettingsRepository.cs
index b2287918..6849409d 100644
--- a/AsbCloudApp/Services/IUserSettingsRepository.cs
+++ b/AsbCloudApp/Services/IUserSettingsRepository.cs
@@ -25,7 +25,7 @@ namespace AsbCloudApp.Services
         /// <param name="key"></param>
         /// <param name="token"></param>
         /// <returns></returns>
-        Task<System.Text.Json.JsonDocument> GetOrDefaultAsync(int userId, string key, CancellationToken token);
+        Task<System.Text.Json.JsonDocument?> GetOrDefaultAsync(int userId, string key, CancellationToken token);
 
         /// <summary>
         /// Добавить или изменить настройки с ключем для пользователя
diff --git a/AsbCloudInfrastructure/Repository/UserSettingsRepository.cs b/AsbCloudInfrastructure/Repository/UserSettingsRepository.cs
index f8451d02..8754b3c1 100644
--- a/AsbCloudInfrastructure/Repository/UserSettingsRepository.cs
+++ b/AsbCloudInfrastructure/Repository/UserSettingsRepository.cs
@@ -16,7 +16,7 @@ namespace AsbCloudInfrastructure.Repository
             this.context = context;
         }
 
-        public Task<System.Text.Json.JsonDocument> GetOrDefaultAsync(int userId, string key, CancellationToken token)
+        public Task<System.Text.Json.JsonDocument?> GetOrDefaultAsync(int userId, string key, CancellationToken token)
             => context.Set<UserSetting>()
                 .Where(s => s.IdUser == userId && s.Key == key)
                 .Select(s => s.Value)
diff --git a/AsbCloudWebApi/AsbCloudWebApi.csproj b/AsbCloudWebApi/AsbCloudWebApi.csproj
index 4a1f5733..5f231625 100644
--- a/AsbCloudWebApi/AsbCloudWebApi.csproj
+++ b/AsbCloudWebApi/AsbCloudWebApi.csproj
@@ -6,6 +6,7 @@
 	<ServerGarbageCollection>true</ServerGarbageCollection>
 	<NoWarn>$(NoWarn);1591</NoWarn>
 	<UserSecretsId>80899ceb-210f-4f19-ac56-aa90a5d666d4</UserSecretsId>
+	<Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/AsbCloudWebApi/Controllers/SAUB/DetectedOperationController.cs b/AsbCloudWebApi/Controllers/SAUB/DetectedOperationController.cs
index 244528a3..ee3ba8f3 100644
--- a/AsbCloudWebApi/Controllers/SAUB/DetectedOperationController.cs
+++ b/AsbCloudWebApi/Controllers/SAUB/DetectedOperationController.cs
@@ -145,7 +145,7 @@ namespace AsbCloudWebApi.Controllers.SAUB
             else
             {
                 if (!await wellService.IsCompanyInvolvedInWellAsync((int)idCompany,
-                    (int)idWell, token).ConfigureAwait(false))
+                    idWell!.Value, token).ConfigureAwait(false))
                     return Forbid();
                 idsWells = new List<int> { (int)idWell };
             }
diff --git a/AsbCloudWebApi/Middlewares/SimplifyExceptionsMiddleware.cs b/AsbCloudWebApi/Middlewares/SimplifyExceptionsMiddleware.cs
index dd9fff9f..589d8f9f 100644
--- a/AsbCloudWebApi/Middlewares/SimplifyExceptionsMiddleware.cs
+++ b/AsbCloudWebApi/Middlewares/SimplifyExceptionsMiddleware.cs
@@ -19,7 +19,7 @@ namespace AsbCloudWebApi.Middlewares
         {
             try
             {
-                await next?.Invoke(context);
+                await next.Invoke(context);
             }
             catch (ArgumentInvalidException ex)
             {
diff --git a/AsbCloudWebApi/PermissionAttribute.cs b/AsbCloudWebApi/PermissionAttribute.cs
index 7eeff776..1249b531 100644
--- a/AsbCloudWebApi/PermissionAttribute.cs
+++ b/AsbCloudWebApi/PermissionAttribute.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Runtime.CompilerServices;
 
 namespace AsbCloudWebApi
 {
@@ -8,7 +9,7 @@ namespace AsbCloudWebApi
     {
         public static SortedSet<string> Registered { get; } = new SortedSet<string>();
 
-        public string Name { get; set; }
+        public string Name { get; set; } = null!;
 
         /// <summary>
         /// Проверка наличия у пользователя разрешения с именем "{ControllerName}.{http_method}".
diff --git a/AsbCloudWebApi/TraceListenerView.cs b/AsbCloudWebApi/TraceListenerView.cs
deleted file mode 100644
index bda66d1c..00000000
--- a/AsbCloudWebApi/TraceListenerView.cs
+++ /dev/null
@@ -1,27 +0,0 @@
-using System.Diagnostics;
-
-namespace AsbCloudWebApi
-{
-    public class TraceListenerView : TraceListener
-    {
-        public TraceListenerView()
-        {
-            Trace.Listeners.Add(this);
-        }
-
-        public override void Write(object o)
-        {
-            base.Write(o);
-        }
-
-        public override void Write(string message)
-        {
-            //throw new NotImplementedException();
-        }
-
-        public override void WriteLine(string message)
-        {
-            //throw new NotImplementedException();
-        }
-    }
-}