As almost every piece of software Visual Studio behaves strangely from time to time, weird error messages, crashes,… I’ve seen it all. A first help to trace the source of the problem is to start Visual Studio with logging enabled. You can do this by starting Visual Studio with the /log switch:
devenv.exe /log [filename]
The [filename] is optional and if not specified will call the log ActivityLog.xml by default. The path is to the file is:
%APPDATA%\Microsoft\VisualStudio\<version>\ActivityLog.xml
There is an XML stylesheet (XSL) comes with the XML data so if you view the file in your browser you will see this nice view: