7.0.6 Client getting System.AccessViolationException: Attempted to read or write protected memory.

[APahlka]

I have a .Net 10 server/client which was updated from 6.1.7 to 7.0.6 and after a few calls to a Unary call that has a shape like:

UnaryResult GetDigitalTypeMappings(int? mapId)

where the mapId is null, I get:

Fatal error.
System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
at Grpc.Net.Client.Internal.StreamExtensions+d__91[[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].MoveNext() at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[[Grpc.Net.Client.Internal.StreamExtensions+<WriteMessageAsync>d__91[[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]], Grpc.Net.Client, Version=2.0.0.0, Culture=neutral, PublicKeyToken=d754f35622e28bad]](d__91<System.__Canon> ByRef) at System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[[Grpc.Net.Client.Internal.StreamExtensions+<WriteMessageAsync>d__91[[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]], Grpc.Net.Client, Version=2.0.0.0, Culture=neutral, PublicKeyToken=d754f35622e28bad]](d__91<System.__Canon> ByRef) at Grpc.Net.Client.Internal.StreamExtensions.WriteMessageAsync[[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]](System.IO.Stream, Grpc.Net.Client.Internal.GrpcCall, System.__Canon, System.Action2<System.__Canon,Grpc.Core.SerializationContext>, Grpc.Core.CallOptions)
at Grpc.Net.Client.Internal.GrpcCall2[[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].WriteMessageAsync(System.IO.Stream, System.__Canon, Grpc.Core.CallOptions) at Grpc.Net.Client.Internal.GrpcCall2[[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].g__WriteAsync|60_0(System.__Canon, System.IO.Stream)
at Grpc.Net.Client.Internal.PushUnaryContent2[[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].SerializeToStreamAsync(System.IO.Stream, System.Net.TransportContext) at System.Net.Http.Http2Connection+Http2Stream+<SendRequestBodyAsync>d__45.MoveNext() at System.Net.Http.Http2Connection+Http2Stream.SendRequestBodyAsync(System.Threading.CancellationToken) at System.Net.Http.Http2Connection+<SendAsync>d__111.MoveNext() at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object) at System.Runtime.CompilerServices.AsyncTaskMethodBuilder1+AsyncStateMachineBox1[[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.Net.Http.Http2Connection+<SendAsync>d__111, System.Net.Http, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a]].MoveNext() at System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action, Boolean) at System.Threading.Tasks.Task.RunContinuations(System.Object) at System.Net.Http.Http2Connection+<SendHeadersAsync>d__97.MoveNext() at System.Runtime.CompilerServices.AsyncTaskMethodBuilder1+AsyncStateMachineBox1[[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.Net.Http.Http2Connection+<SendHeadersAsync>d__97, System.Net.Http, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a]].ExecutionContextCallback(System.Object) at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object) at System.Runtime.CompilerServices.AsyncTaskMethodBuilder1+AsyncStateMachineBox1[[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.Net.Http.Http2Connection+<SendHeadersAsync>d__97, System.Net.Http, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a]].MoveNext(System.Threading.Thread) at System.Runtime.CompilerServices.AsyncTaskMethodBuilder1+AsyncStateMachineBox`1[[System.__Canon, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.Net.Http.Http2Connection+d__97, System.Net.Http, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a]].MoveNext()
at System.Threading.Tasks.AwaitTaskContinuation.System.Threading.IThreadPoolWorkItem.Execute()
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading.PortableThreadPool+WorkerThread.WorkerThreadStart()
at System.Threading.Thread.StartCallback()

If the mapId is not null, it does not have the issue. When I put the client back to version 6.1.7, it does not have the error.

For the gRPC nuget packages, I am using Grpc.Net.Client version 2.71.0

I have also tried with the 7.0.8 client and have the same issue.

I also tried using a Framework 4.8 client and I only get this:
Unhandled Exception: System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
at MagicOnion.Internal.GrpcMethodHelper.<>c__DisplayClass8_01.<CreateBoxedMarshaller>b__0(Box1 obj, SerializationContext ctx)
at Grpc.Core.Internal.AsyncCallBase2.UnsafeSerialize(TWrite msg, DefaultSerializationContext context) at Grpc.Core.Internal.AsyncCall2.UnaryCallAsync(TRequest msg)
at Grpc.Core.Calls.AsyncUnaryCall[TRequest,TResponse](CallInvocationDetails2 call, TRequest req) at Grpc.Core.DefaultCallInvoker.AsyncUnaryCall[TRequest,TResponse](Method2 method, String host, CallOptions options, TRequest request)
at MagicOnion.Client.Internal.RawMethodInvoker4.<.ctor>b__2_0(RequestContext context) at MagicOnion.Client.Internal.InterceptInvokeHelper.InvokeWithFilter(RequestContext context) at MagicOnion.Client.Internal.RawMethodInvoker4.d__5.MoveNext()
at System.Runtime.CompilerServices.AsyncTaskMethodBuilder1.Start[TStateMachine](TStateMachine& stateMachine) at MagicOnion.Client.Internal.RawMethodInvoker4.InvokeUnaryCore(MagicOnionClientBase client, String path, TRequest request, Func2 requestMethod) at MagicOnion.Client.Internal.RawMethodInvoker4.InvokeUnary(MagicOnionClientBase client, String path, TRequest request)
at MagicOnion.DynamicallyGeneratedClient.dataPARC.Store.Service.Interfaces.IConfigurationServiceClient.GetDigitalTypeMappings(Nullable`1 )

Let me know what other information you would like to help troubleshoot this issue. Thank you for any help you can give.

[APahlka]

I figured this might be hard to understand, so I created a sample server/client using version MagicOnion 7.0.9.
https://github.com/APahlka/MagicOnionBugDemo

I run the server via Visual Studio 2026 and then manually ran the client via Windows terminal. I hope this helps.