It happens on start, Visual Studio CPU usage goes to 50% on an hyperthreading machine and it hangs. Then after 3-5 minutes Visual Studio becomes responsive and it is possible to use it for a while and then it happens again, randomly.
Disabling R# solves the problem in VB. No problems in C#.
Attached is the stacktrace taken from another instance of VS.
It looks like it's a deadlock on a WriterLock.
Using process explorer I identified the thread that is hanging VS:
And the stacktrace from process explorer: