How do I install a VSIX file in Visual Studio?
VSIX is a Visual Studio extension installer. You must have Visual Studio 2010 or newer in order to install them, but you should be able to install it by double-clicking the .vsix file. Alternatively you should be able to install it from within the VS Extension Manager (Tools->Extension Manger)
See more about VSIX files at Quan To's Visual Studio Extensibility blog
The above answers didn't help me; I couldn't install it through the extension manager and there was not default application for .vsix. However, I needed to open it (right click > Open with...) with Microsoft Visual Studio Version Selector and it worked.
Small update: For VS 2013, you need the corresponding version of NuGet: http://visualstudiogallery.msdn.microsoft.com/4ec1526c-4a8c-4a84-b702-b21a8f5293ca. Otherwise, the version selecter will tell you it's already installed on all fitting versions.
How to install Visual Studio Extensions
To summarise, there are three options:
- Install via Extension Manager (Tools/Options)
- Install via Visual Studio Gallery.com (download and open directly or save then double-click)
- Install via "xcopy" into %localappdata%\Microsoft\VisualStudio\10.0\Extensions