Sorry to heard about that, unfortunately, we are unable to reproduce this issue :-(
When an error occur with vsixinstaller, it should provide you the install log. Could you share the log file?
Could you share a screenshot of the error message if you don't have this kind of error ?
Sometimes, .vsix is not tied to the correct vsixinstaller.exe executable. Try to install the vsix using command line with the following command :
VSIXInstaller is located under "C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\" for VS2015 or "C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE\" for VS2013