We have a (previously) functioning 64 bit app that connects to Telegram API. It uses .Net framework. Before last week, it ran perfectly well, using TDLib.API.dll and TDLib.dll that were v 1.7.9. According to Telegram, these versions should work but they don’t.

We updated these to 1.8.3 (latest release). In Visual Studio IDE the app runs fine and connects to the API like it should. Once compiled, it connects in some Windows machines and not in others (Windows Server, and some versions of Win 10). The ones that don’t connect, crash after entering phone number.

The errors we get are Visual C related errors.

Application: (app name)
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.AccessViolationException
at .td.ClientManager.execute(td.tl.unique_ptr<td::td_api::Object>, td.tl.unique_ptr<td::td_api::Function>)
at Telegram.Td.Client.Execute(Telegram.Td.Api.Function)
at ChannelWriter.Telegram.Agent+d__25.MoveNext()
at System.Runtime.CompilerServices.AsyncVoidMethodBuilder.Start[[ChannelWriter.Telegram.Agent+d__25, ChannelWriter, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]](d__25 ByRef)
at ChannelWriter.Telegram.Agent.OnDoWork(System.ComponentModel.DoWorkEventArgs)
at System.ComponentModel.BackgroundWorker.WorkerThreadStart(System.Object)
at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr, System.Object[], System.Object, System.Object[] ByRef)
at System.Runtime.Remoting.Messaging.StackBuilderSink.AsyncProcessMessage(System.Runtime.Remoting.Messaging.IMessage, System.Runtime.Remoting.Messaging.IMessageSink)
at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
at System.Threading.ThreadPoolWorkQueue.Dispatch()

Any suggestions?

This connects on some Windows machines with no issues at all. Others crash and give the above error, or an error related to MSVCP140.dll. We’ve uninstalled/reinstalled all Visual C++ versions, experimented with different file types, etc. No luck.