When uninstalling/upgrading Plastic, it seems it sometimes silently fails to remove the Visual Studio plugin. This leads to an error message during installation, saying that the vsixinstaller.exe command line finished with an error. In fact, this error you get from vsixinstaller can be simply that the plugin is already installed in all clients (which you can discover by running the same command line interactively from cmd). It would be nice if this "non-fatal" error is detected and reported as such, instead of reporting a generic error message...