That is also a scenario where de-registration/uninstall/re-install/re-registration can help. If you want to try it, here is how:
To deactivate the license: go into "Scanner Settings..", navigate to the License tab, click View license details, then deactivate.
Then do a manual uninstall of Stablebit Scanner.
Re-download the latest version, to be sure your first copy wasn't bad in some way.
I find cleaning out Windows temp files to be helpful, especially with botched or damaged installations. Tools like CCleaner, Wise Disk Cleaner/Wise Registry Cleaner, etc.
Re-install, and then re-activate your copy with your activation key.