This has been recurring for me also and seems to be connected to extension updates but I have not yet been able to blame anything specific. What I have been able to discover is a less intrusive resolution.
In my case deleting the contents of this directory allows the IDE to recover:
%LocalAppData%\Microsoft\VisualStudio\14.0\ComponentModelCache
Edit: I just came across this one which might be handy too – Clear MEF Component Cache (Open VSIX Gallery)