Workflow Manager Backedend is crashing

Question

Workflow Manager Backedend service crashes on exception. I have found following entry in log:

WorkflowSessionConfigurationFailedException was swallowed at location 

DispatchLoopInstanceAsyncResult.Isolate. Microsoft.Activities.Dispatcher.WorkflowSessionConfigurationFailedException ---> System.TypeLoadException: Method 'SubscribeCurrent' in type 'Microsoft.Activities.Hosting.HostedNotificationExtension' from assembly 'Microsoft.Activities.Hosting, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' does not have an implementation.
   at Microsoft.Activities.Hosting.WorkflowSession.ConfigureEnvironment(Activity workflowDefinition, IWorkflowConfiguration workflowConfiguration, IEnumerable`1 hostExtensions)
   at Microsoft.Activities.Dispatcher.DispatchLoopInstanceAsyncResult.ConfigureWorkflowSessionEnvironment(MessageSessionContext messageSession, WorkflowSession workflowSession, Activity rootActivity, IWorkflowConfiguration workflowConfiguration)
   --- End of inner exception stack trace ---
   at Microsoft.Workflow.Common.AsyncResult.End[TAsyncResult](IAsyncResult result)
   at Microsoft.Activities.Dispatcher.DispatchLoopInstanceAsyncResult.WorkflowSessionCreated(IAsyncResult result)
   at Microsoft.Activities.Dispatcher.DispatchLoopInstanceAsyncResult.Isolate(AsyncCompletion callback, IAsyncResult result)

And also this (whis is probably result of previous):

Dispatcher encountered an unexpected exception: System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.Activities.Dispatcher.DispatchLoopInstanceAsyncResult.SystemSuspendSessionOnFailedConfiguration(String suspensionReason)
   at Microsoft.Activities.Dispatcher.DispatchLoopInstanceAsyncResult.SystemSuspendSession(String suspensionReason, SystemSuspendType suspendType)
   at Microsoft.Activities.Dispatcher.DispatchLoopInstanceAsyncResult.Isolate(AsyncCompletion callback, IAsyncResult result)
   at Microsoft.Activities.Dispatcher.DispatchLoopInstanceAsyncResult.Isolate(AsyncCompletion callback, IAsyncResult result)
   at Microsoft.Activities.Dispatcher.DispatchLoopInstanceAsyncResult.ExceptionHandlingFrame(IAsyncResult result)

Have anybody seen an error like this?

I tried to competely uninstall workflow manager, app fabric and service bus, deleted config databases and installed it all again + I installed all latest updates.

It seems like some mismatch in dll versions or an bug.

Answer 1

I found solution. The problem was caused by library Microsoft.Activities.dll (which is by default placed in c:\Program Files\Reference Assemblies\Microsoft\Workflow Manager\1.0\).

After some update, it has a newer version then Workflow Manager Backend. I found, I had 1.0.40131.0 version of workflow manager backend (c:\Program Files\Workflow Manager\1.0\Workflow\Artifacts\Microsoft.Workflow.ServiceHost.exe) and Microsoft.Activities was NEWER and incompatibile.

I took Microsoft.Activities.dll from a server, where it was in 1.0.40131.0 version, replaced in my broken server, restarted backend service and suddenly it started working.

Answer 2

I had this same problem and tried both of the solutions above and frustratingly neither of them worked. What worked for me was doing a workflow cumulative update that updated the Microsoft.Activites.dll to the latest version (1.1.10607.2) where the "Subscribe Current" method being called was actually available after the cumulative update was applied.