Installing Visual Studio 2015 Update 1 give me lots of : “package did not load correctly”

Question

I installed VS2015 with update 1 on Windows 7 Entreprise English over Visual Studio 2015. The setup result was some error(s). I Restarted my machine and run the setup again. The

Answer 1

I had to do a combination of the other answers, none of which was uninstalling VS

1. I renamed C:\Users\{User}\AppData\Local\Microsoft\VisualStudio\14.0
2. started VS2015
3. closed it down
4. did the binding redirect for System.Collections.Immutable from https://stackoverflow.com/a/34018770/57883

Then I've been copying the extensions I think are safe over and seeing if projects all still load.