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c#.netwindowsdynamics-crmdynamics-crm-2011

Dynamics CRM 2011 SyncWorkflowExecutionPlugin unable to find assembly

A strange error suddenly cropped up on our Dynamics CRM 2011 server - a specific plugin assembly can not be found when the plugin execution is triggered through a workflow process, with the error:

[Microsoft.Crm.ObjectModel: Microsoft.Crm.ObjectModel.SyncWorkflowExecutionPlugin]
[324f29aa-6082-ea11-80ee-005056837add: ]
Starting sync workflow 'workflow name', Id: 2d4f29aa-6082-ea11-80ee-005056837add
Sync workflow 'workflow name' terminated with error 'The type initializer for '<Module>' threw an exception.'

And exception stack trace ultimately leads to:

Inner Exception: <CrtImplementationDetails>.ModuleLoadException: The C++ module failed to load while attempting to initialize the default appdomain.

at <CrtImplementationDetails>.ThrowModuleLoadException(String errorMessage, Exception innerException)
at <CrtImplementationDetails>.LanguageSupport.Initialize(LanguageSupport* )
at .cctor()
Inner Exception: System.Runtime.Serialization.SerializationException: Unable to find assembly 'AssemblyName, Version=8.75.0.267, Culture=neutral, PublicKeyToken=4e4051c21cef725b'.

The assembly is present on the server, version, culture, and public key token all match. Oddly enough the plugin steps work fine when the execution is triggered directly through a create/update/etc request - it's only when the execution is triggered through a workflow that the error occurs. And by triggered through a workflow I don't mean running code activity from that assembly, I mean a situation like:

  • Entity is created
  • OnCreate plugin from Assembly1 runs without issues
  • Workflow runs that updates a related entity, triggering OnUpdate plugin from Assembly1 - ERROR

This issue cropped up initially after a server restart. Another restart fixed it temporarily, until two days later it started happening again. We've tried everything we can think of - updating the assembly, unregistering/re-registering it, restarting all services, restarting the server again. Does anyone have any idea what might be the cause of this and how to fix it?

Solution

  • We discovered the issue was caused by a Windows update that had been applied before the initial restart, which had installed .NET framework v4.8 on the server. Although the application was still using an older version, apparently just having v4.8 installed was enough to cause errors. Reverting back to an earlier .NET version fixed the problem.

    I am not certain what is the exact technical reason for this - seems to be something related to App Domains (https://learn.microsoft.com/en-us/dotnet/api/system.appdomain?view=netframework-4.8). But if you encounter a similar issue, check your .NET framework version.