I just fixed a very slow running VS 2015 by deleting the ComponentModelCache folder. It now snaps open!
This has dogged me now for a few weeks and had tried everything before, blamed extensions and Resharper, but nothing fixed it.
Mine was in C:\Users\MyName\AppData\Local\Microsoft\VisualStudio\15.0_8a1dd55a
Close all Visual Studio Instances.
Remove the %LocalAppData%\Microsoft\VisualStudio\12.0\ComponentModelCache folder.
Start Visual Studio.
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