Microsoft.Data.SqlClient.SNINativeMethodWrapper.UnmanagedIsTokenRestricted can't read sni.dll on IIS with custom apppool Identity

We’re seeing sni.dll error with old asp.net mvc 5 project(net4.8) with Microsoft.EntityFrameworkCore* 3.1.2 installed(and Microsoft.Data.SqlClient.SNI v1.1.1 too). The problem only on full IIS with custom account Identity in app pool configured. Locally on IISExpress all works fine.

Workound for us is to copy C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App\2.*.…sni.dll to application/bin/x64 and replace. (found here https://github.com/dotnet/SqlClient/issues/385)

Is there some more convinient solution of this problem?

Exception message:
System.TypeInitializationException
The type initializer for 'Microsoft.Data.SqlClient.SNINativeMethodWrapper' threw an exception.
Stack trace:
System.TypeInitializationException: The type initializer for 'Microsoft.Data.SqlClient.SNINativeMethodWrapper' threw an exception. ---> System.ComponentModel.Win32Exception: Failed to load C:\www\site3\site\bin\x64\SNI.dll ---> System.ComponentModel.Win32Exception: The specified module could not be found
   --- End of inner exception stack trace ---
   at Microsoft.Data.SqlClient.SNINativeMethodWrapper..cctor()
   --- End of inner exception stack trace ---
   at Microsoft.Data.SqlClient.SNINativeMethodWrapper.UnmanagedIsTokenRestricted(IntPtr token, Boolean& isRestricted)
   at Microsoft.Data.Win32NativeMethods.IsTokenRestrictedWrapper(IntPtr token)
   at Microsoft.Data.ProviderBase.DbConnectionPoolIdentity.GetCurrent()
   at Microsoft.Data.ProviderBase.DbConnectionPoolGroup.GetConnectionPool(DbConnectionFactory connectionFactory)
   at Microsoft.Data.ProviderBase.DbConnectionFactory.GetConnectionPool(DbConnection owningObject, DbConnectionPoolGroup connectionPoolGroup)
   at Microsoft.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
   at Microsoft.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
   at Microsoft.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry)
   at Microsoft.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
   at Microsoft.Data.SqlClient.SqlConnection.Open()
   at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.OpenDbConnection(Boolean errorsExpected)
   at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.Open(Boolean errorsExpected)
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReader(RelationalCommandParameterObject parameterObject)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.InitializeReader(DbContext _, Boolean result)
   at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.MoveNext()
   at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
   at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
   at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)

[chromigo]

Well, I have resolved problem. TLDR: had Microsoft Visual C++ 2015 Redistributable x86 but had not x64.

Details: The exception contains

System.ComponentModel.Win32Exception: The specified module could not be found specified module is keyword here. sni.dll is ok, but probably he still has dependencies.

So I looked at https://github.com/dotnet/SqlClient/issues/211 and https://github.com/dotnet/SqlClient/issues/361 I already checked that machine has Microsoft Visual C++ 2015 Redistributable installed. But it was only x86 version… Installing x64 solved the problem.

It’s strange, because here https://github.com/dotnet/SqlClient/issues/361#issuecomment-594759511 say that “we have removed dependency on VC Runtime, so you don’t need that installed on your client”. I have 1.1.1 version of Microsoft.Data.SqlClient but it look like he still need visual c++ 2015. binding redirect

<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Data.SqlClient" publicKeyToken="23ec7fc2d6eaa4a5" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-1.11.20045.2" newVersion="1.11.20045.2" />
      </dependentAssembly>
    </assemblyBinding>

[cheenamalhotra]

@chromigo

That’s great to know!

I have 1.1.1 version of Microsoft.Data.SqlClient but it look like he still need visual c++ 2015.

You should have reference to Microsoft.Data.SqlClient.SNI v1.1.1 that does not depend on VC++ Redist packages any more.