diff --git a/AsbCloudInfrastructure/DependencyInjection.cs b/AsbCloudInfrastructure/DependencyInjection.cs
index 62fa5d3f..496e4729 100644
--- a/AsbCloudInfrastructure/DependencyInjection.cs
+++ b/AsbCloudInfrastructure/DependencyInjection.cs
@@ -26,6 +26,7 @@ using System;
 
 namespace AsbCloudInfrastructure
 {
+#nullable enable
     public static class DependencyInjection
     {
         public static IAsbCloudDbContext MakeContext(string connectionString)
@@ -49,7 +50,7 @@ namespace AsbCloudInfrastructure
 
             TypeAdapterConfig.GlobalSettings.Default.Config
                 .ForType<TimeDto, TimeOnly>()
-                .MapWith((source) => source == default ? default : source.MakeTimeOnly());
+                .MapWith((source) => source.MakeTimeOnly());
 
             TypeAdapterConfig.GlobalSettings.Default.Config
                 .ForType<TimeOnly, TimeDto>()
@@ -59,6 +60,7 @@ namespace AsbCloudInfrastructure
                 .ForType<TimeOnly, TimeDto>()
                 .MapWith((source) => new(source));
 
+#pragma warning disable CS8603 // Possible null reference return.
             TypeAdapterConfig.GlobalSettings.Default.Config
                 .ForType<WellDto, Well>()
                 .Ignore(dst => dst.Cluster,
@@ -68,6 +70,7 @@ namespace AsbCloudInfrastructure
                     dst => dst.WellCompositeSrcs,
                     dst => dst.WellOperations,
                     dst => dst.WellType);
+#pragma warning restore CS8603 // Possible null reference return.
 
             TypeAdapterConfig.GlobalSettings.Default.Config
                 .ForType<ClusterDto, Cluster>()
@@ -93,7 +96,7 @@ namespace AsbCloudInfrastructure
             
 
             services.AddMemoryCache();
-            services.AddScoped<IAsbCloudDbContext>(provider => provider.GetService<AsbCloudDbContext>());
+            services.AddScoped<IAsbCloudDbContext>(provider => provider.GetRequiredService<AsbCloudDbContext>());
             services.AddScoped<IEmailService, EmailService>();
 
             services.AddSingleton(new WitsInfoService());
@@ -140,25 +143,25 @@ namespace AsbCloudInfrastructure
             // admin crud services:
             services.AddTransient<ICrudRepository<TelemetryDto>, CrudCacheRepositoryBase<TelemetryDto, Telemetry>>(s =>
                 new CrudCacheRepositoryBase<TelemetryDto, Telemetry>(
-                    s.GetService<IAsbCloudDbContext>(),
-                    s.GetService<IMemoryCache>(),
+                    s.GetRequiredService<IAsbCloudDbContext>(),
+                    s.GetRequiredService<IMemoryCache>(),
                     dbSet => dbSet.Include(t => t.Well))); // может быть включен в сервис TelemetryService
             services.AddTransient<ICrudRepository<DepositDto>, CrudCacheRepositoryBase<DepositDto, Deposit>>(s =>
                 new CrudCacheRepositoryBase<DepositDto, Deposit>(
-                    s.GetService<IAsbCloudDbContext>(),
-                    s.GetService<IMemoryCache>(),
+                    s.GetRequiredService<IAsbCloudDbContext>(),
+                    s.GetRequiredService<IMemoryCache>(),
                     dbSet => dbSet.Include(d => d.Clusters)));
             services.AddTransient<ICrudRepository<CompanyDto>, CrudCacheRepositoryBase<CompanyDto, Company>>(s =>
                 new CrudCacheRepositoryBase<CompanyDto, Company>(
-                    s.GetService<IAsbCloudDbContext>(),
-                    s.GetService<IMemoryCache>(),
+                    s.GetRequiredService<IAsbCloudDbContext>(),
+                    s.GetRequiredService<IMemoryCache>(),
                     dbSet => dbSet.Include(c => c.CompanyType)));
 
             services.AddTransient<ICrudRepository<CompanyTypeDto>, CrudCacheRepositoryBase<CompanyTypeDto, CompanyType>>();
             services.AddTransient<ICrudRepository<ClusterDto>, CrudCacheRepositoryBase<ClusterDto, Cluster>>(s =>
                 new CrudCacheRepositoryBase<ClusterDto, Cluster>(
-                    s.GetService<IAsbCloudDbContext>(),
-                    s.GetService<IMemoryCache>(),
+                    s.GetRequiredService<IAsbCloudDbContext>(),
+                    s.GetRequiredService<IMemoryCache>(),
                     dbSet => dbSet
                         .Include(c => c.Wells)
                         .Include(c => c.Deposit))); // может быть включен в сервис ClusterService
@@ -200,7 +203,7 @@ namespace AsbCloudInfrastructure
             where TService : class
             where TImplementation : class, TService
             => services.AddTransient<TService, TImplementation>()
-            .AddTransient(provider => new Lazy<TService>(provider.GetService<TService>));
+            .AddTransient(provider => new Lazy<TService>(provider.GetRequiredService<TService>));
 
         public static IServiceCollection AddTransientLazy<TService, TImplementation>(this IServiceCollection services, Func<IServiceProvider, TImplementation> implementationFactory)
             where TService : class
@@ -209,4 +212,5 @@ namespace AsbCloudInfrastructure
             .AddTransient(provider => new Lazy<TService>(() => implementationFactory(provider)));
 
     }
+#nullable disable
 }
diff --git a/AsbCloudInfrastructure/Services/MeasureService.cs b/AsbCloudInfrastructure/Services/MeasureService.cs
index 56157786..d32a7882 100644
--- a/AsbCloudInfrastructure/Services/MeasureService.cs
+++ b/AsbCloudInfrastructure/Services/MeasureService.cs
@@ -13,6 +13,7 @@ using System.Threading.Tasks;
 
 namespace AsbCloudInfrastructure.Services
 {
+#nullable enable
     public class MeasureService : IMeasureService
     {
         private readonly IAsbCloudDbContext db;
@@ -40,7 +41,7 @@ namespace AsbCloudInfrastructure.Services
             return cache;
         }
 
-        public async Task<MeasureDto> GetLastAsync(int idWell, int idCategory, CancellationToken token)
+        public async Task<MeasureDto?> GetLastOrDefaultAsync(int idWell, int idCategory, CancellationToken token)
         {
             var query = db.Measures
                 .Include(m => m.Category)
@@ -54,8 +55,11 @@ namespace AsbCloudInfrastructure.Services
                 .ConfigureAwait(false);
 
             var timezone = wellService.GetTimezone(idWell);
-            var dto = Convert(entity, timezone.Hours);
-            return dto;
+
+            if (entity is null)
+                return null;
+
+            return Convert(entity, timezone.Hours);
         }
 
         public async Task<IEnumerable<MeasureDto>> GetHisoryAsync(int idWell, int? idCategory = null, CancellationToken token = default)
@@ -124,6 +128,9 @@ namespace AsbCloudInfrastructure.Services
                 .FirstOrDefaultAsync(token)
                 .ConfigureAwait(false);
 
+            if (entity is null)
+                throw new ArgumentInvalidException($"Measure doesn't exist", nameof(idWell));
+
             entity.IsDeleted = true;
 
             return await db.SaveChangesAsync(token).ConfigureAwait(false);
@@ -140,16 +147,16 @@ namespace AsbCloudInfrastructure.Services
         private MeasureDto Convert(Measure entity, double hours)
         {
             var dto = entity.Adapt<MeasureDto>();
-            dto.CategoryName = entity.Category?.Name;
+            dto.CategoryName = entity.Category?.Name ?? String.Empty;
             dto.Timestamp = entity.Timestamp.ToRemoteDateTime(hours);
             return dto;
         }
         private Measure Convert(MeasureDto dto, double hours)
         {
             var entity = dto.Adapt<Measure>();
-            entity.Category = null;
             entity.Timestamp = dto.Timestamp.ToUtcDateTimeOffset(hours);
             return entity;
         }
     }
+#nullable disable
 }
diff --git a/AsbCloudInfrastructure/Services/WellOperationService/WellOperationImportService.cs b/AsbCloudInfrastructure/Services/WellOperationService/WellOperationImportService.cs
index e9ed3d11..fe8c77d1 100644
--- a/AsbCloudInfrastructure/Services/WellOperationService/WellOperationImportService.cs
+++ b/AsbCloudInfrastructure/Services/WellOperationService/WellOperationImportService.cs
@@ -11,6 +11,7 @@ using System.Linq;
 
 namespace AsbCloudInfrastructure.Services.WellOperationService
 {
+#nullable enable
     /*
      * password for WellOperationImportTemplate.xlsx is ASB2020!
      */
@@ -36,7 +37,7 @@ namespace AsbCloudInfrastructure.Services.WellOperationService
 
         private readonly IAsbCloudDbContext db;
         private readonly IWellService wellService;
-        private List<WellOperationCategory> categories = null;
+        private List<WellOperationCategory> categories = null!;
         public List<WellOperationCategory> Categories
         {
             get
@@ -52,7 +53,7 @@ namespace AsbCloudInfrastructure.Services.WellOperationService
             }
         }
 
-        private List<WellSectionType> sections = null;
+        private List<WellSectionType> sections = null!;
         public List<WellSectionType> Sections
         {
             get
@@ -92,9 +93,6 @@ namespace AsbCloudInfrastructure.Services.WellOperationService
                 .AsNoTracking()
                 .ToList();
 
-            if (!operations.Any())
-                return null;
-
             var timezone = wellService.GetTimezone(idWell);
 
             return MakeExelFileStream(operations, timezone.Hours);
@@ -102,8 +100,12 @@ namespace AsbCloudInfrastructure.Services.WellOperationService
 
         public Stream GetExcelTemplateStream()
         {
+            var resourceName = System.Reflection.Assembly.GetExecutingAssembly()
+                .GetManifestResourceNames()
+                .FirstOrDefault(n => n.EndsWith("WellOperationImportTemplate.xlsx"))!;
+
             var stream = System.Reflection.Assembly.GetExecutingAssembly()
-                .GetManifestResourceStream("AsbCloudInfrastructure.Services.WellOperationService.WellOperationImportTemplate.xlsx");
+                .GetManifestResourceStream(resourceName)!;
             return stream;
         }
 
@@ -126,14 +128,16 @@ namespace AsbCloudInfrastructure.Services.WellOperationService
             if (planOperations.Any())
             {
                 var sheetPlan = workbook.Worksheets.FirstOrDefault(ws => ws.Name == sheetNamePlan);
-                AddOperationsToSheet(sheetPlan, planOperations, timezoneOffset);
+                if (sheetPlan is not null)
+                    AddOperationsToSheet(sheetPlan, planOperations, timezoneOffset);
             }
 
             var factOperations = operations.Where(o => o.IdType == 1);
             if (factOperations.Any())
             {
                 var sheetFact = workbook.Worksheets.FirstOrDefault(ws => ws.Name == sheetNameFact);
-                AddOperationsToSheet(sheetFact, factOperations, timezoneOffset);
+                if (sheetFact is not null)
+                    AddOperationsToSheet(sheetFact, factOperations, timezoneOffset);
             }
         }
 
@@ -328,4 +332,5 @@ namespace AsbCloudInfrastructure.Services.WellOperationService
             return operation;
         }
     }
+#nullable disable
 }