I was debugging my new app to my phone earlier and got the following really helpful (not…) error message in Visual Studio.
Error : DEP0001 : Unexpected Error: Install failed. Please contact your software vendor. (Exception from HRESULT: 0x80073CF9)
After a quick “what the!?” moment it occurred to me that I’d just changed the manifest to use new packaging details and that perhaps the app still installed on the phone couldn’t be uninstalled anymore? I proceeded to uninstalled the app on the phone and Visual Studio was then able to install the new version fine.
Hopefully this might help someone else in a similar situation.