Another poster is experiencing these symptoms, but on Windows 10.
@mjholt In my post above I recommended booting to Safe Mode. But, since you’ve already run a virus scan, before you go the Safe Mode route try either disabling your antivirus or whitelisting Scrivener. We’ve definitely seen AV software interfering with Scrivener’s operations on these forums, so it’s worth a shot.
That said, i am highly suspicious that you and the poster linked above both started experiencing this very odd issue on the same day. So I’m betting some recent update to an app that you both use is at the root of this.
Best,
Jim