I was able to invite myself to the latest build and the app worked fine. However, when trying to update the app to a new build, it fails with "Unable to install". I figured maybe I'd uninstall it and reinstall it, but I'm having a hard time removing it. Uninstall doesn't work, and blowing away any mention of the app through Windows Explorer doesn't seem to do the trick either.
Can anyone point me to the right method of figuring out what's going on?