Unable to reinstall Scrivener 3

I did install S3 some time ago on Windows 7, but forgot to uninstall the previous version. So I did that, but some settings must have been wiped out and S3 wouldn’t run. I uninstalled it, got a new installer and ran that to reinstall it. But now it freezes. The log window says over and over:

Line 0: qsettings regenumvalue failed…

Line 0: qsettings regenumvalue failed…

etc.