I am getting this error on code that used to work. I have not changed the code.
Here is the full error:
The CLR has been unable to transition
One fix for the problem is to go to the Debug -> Exceptions -> Managed Debug Assistants menu in Visual Studio and uncheck the ContextSwitchDeadlock
From http://blog.wpfwonderland.com/2007/08/16/clr-has-been-unable-to-transition-from-com-context-for-60-seconds/
Update: Please, don't downvote, if you fairly think, that workaround is awful idea. A number of people tried a number of solutions listed as answers here, but my workaround was the only thing helped them. That's why the answer still has the positive score.