Visual studio does not install .vsix files

I am not clear whether you want to install or just view the contents of VSIX. If you want to install the extension, you just need to double click it and it will install (Do not try to open it with VS Version selector). If you want to see what is inside VSIX, it is basically an archive. So either try to use program like 7-zip to open it else, rename .vsix to .zip and then unzip it.

Further, there is also a chance that you have wrongly associated vsix files to be opened with Visual Studio. In such a case it will open in Visual Studio any case.

Finally, if you have wrongly associated the vsix to open with Visual Studio, try installing the extension using VSIXInstaller.exe found in C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE\VSIXInstaller.exe

I faced the same issue. Just use the VSIXInstaller to install the extension.

You can open "Developer Command Prompt for VS2012" tool in Start -> Microsoft Visual Studio 2012 -> Visual Studio Tools. On the console, run the below command:

VSIXInstaller <path to vsix file>

1. Open "Developer Command Prompt for VS2015" as administrator.
2. Type VSIXInstaller.exe vsixFilePath

Note that this way wouldn't work with me and gives me "Path to vsix file 'G:\Roslyn' is invaild or you don't have required access permissions". To solve this you need to put the path in a double quote like this:

 VSIXInstaller.exe "G:\Roslyn SDK.vsix"

I got into a weird situation where in a fresh install of W10 and VS2015 Community, the Player Framework vsix installation won't start, either by dbl click or from command prompt using VSIxInstaller.exe, and would show no message at all. The solution was to open an elevated command prompt (run Developer Command Prompt for VS2015 as administrator) and then type VSIXInstaller.exe worked.