How the does it make sense that I need .NET Framework to uninstall VS Build Tools? The installer runs, but then fails. Just delete your damned files and registry keys.

How did you find a machine with no .Net framework installed? What year is this?

@configurator I had installed 4.7, then removed it, because I wanted to make things clean before installing VS. It's on me that I did things out of order, but the included .NET was too old for the uninstaller for both Build Tools 2013 and 2015, and I expect an uninstaller to require very minimal dependencies, especially on Windows.