Today i faced this issue in my IDE and resolved with following steps:
Open Developer Command Prompt for VS2015
Type below command (as it is) in above command line
"C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\devenv.exe" /ResetUserData
This will logout from Visual Studio and remove all user settings (but not data)
Restart Visual Studio and re-login, that's it.
This worked for me and hope this helps you as well.