Several times in the past few months, I have experienced an error loading a solution in Visual Studio 2013 that goes something like:
“The ‘<packagename>’ package did not load correctly.”
Every time that I have had this error, the solution has been to go to the “C:\Users\<user>\AppData\Local\Microsoft\VisualStudio\12.0 folder and delete the ComponentModelCache folder.
I suspect that the contents of the cache folder get corrupted and/or out of sync when the OS shuts down unexpectedly while Visual Studio 2013 is up. It’s annoying, but deleting the ComponentModelCache forces Visual Studio to load without the cache and fixes the problem every time.