I get this error if I try to install Paint.net 4.2.9
Thats not true though, the problem is that my default user and profiles are not inside C:\user\<username>
This also breaks the installation of the VC runtimes, but I could install them manually.I did this with paint.net too, but its quite inconvenient and I would need to capture the registries on a clean PC and apply it to the other desktop to get thumbnails working.
So maybe, an option would be nice to have, e.g change the temp dir. This would be a simple fix that wouldn't require more research.