Comment 6 for bug 1736973

Deleting
  %localappdata%\fontconfig\cache
has no effect whatsoever.

Sure, a reboot helps.

Don't misinform people that this is an issue with Windows. Windows works brilliantly, look at Office for an example wrt font installations/deletions/updates.

This is not a Microsoft/Windows quirk, this is Inkscape (or its dependency) misbehaving. Inkscape is littered with this kind of bugs and major usability issues. As some other otherwise awesome open source software is too, by the way. Being portable is a lot of work, but commit to supporting Windows truly if at all possible. It appears in many ways Inkscape merely compiles and runs. But if you don't, be faithfull about the reason stuff doesn't work as it does on Linux, please.

If I understand it correctly, Inkscape opens .ttf files to get to system fonts. If that is true, this is just done plain wrong. Inkscape should use the proper way to get to system fonts. That the file exists on disk is completely irrelevant. Get a handle. If you then try to uninstall a font and Inkscape is open, Windows just won't do it. If you update, Inkscape will be told the font changed and be given a chance to redraw. Look at Word for the behavior I describe.