Occasionally, for various reasons templates will go missing from the template cache and therefore won’t appear in Visual Studio.A common response to this error is to re-install Visual Studio while this does (usually) work, it is a time consuming process which should be avoided
Luckily, there is another possible solution to this problem that may save you from the pain and loss of productivity associated with having to re-install Visual Studio
Running this command as administrator will re-install templates that came with Visual Studio
This re-installs the templates that ship with Visual Studio as well as those added by add-ons. I’m not sure if it restores user-exported templates because I don’t have any.