Jun 27, 2016 02:58 AM|Angie xu - MSFT|LINK
From your description above, I'd like to suggest you to restart your Visual Studio, and follow steps below to try it again,
In the Extensions and Updates, find the extension you want to
install. (If you know the name or part of the name of the extension, you can search in the Search
Visual Studio Gallery window.) Click Download, then Install. You must restart
Visual Studio in order to load the extension.