Thank you for getting in touch. Apparently this is a known issue with the NSIS installer we care currently using. As I understand it is apparently necessary to use Regedit to find
Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Uninstall
and delete the entries found within. This should solve the issue but unfortunately can't guarantee this and advise caution doing anything with Regedit.
I hope this helps !