Not if ProScan is unregistered. The 30 day fully functional demo/trial still can be used.
If ProScan is registered then a prompt will appear "Remove ProScan activation..."
I just verified this bug after seeing your reply that does not echo my not so recent memory.
On a spared seldom used windows 10 laptop (with all microsoft patch up2date just for the record)
1. Install Proscan for the 1st time ever, open up, all good, reopen ... any way 30 day trial.
2. Wait for at least a day, open up, 29 days left
3. uninstall proscan and
4. manually delete the default c:/proscan folder (not sure if this step is needed to reproduce the bug)
5. reinstall proscan, now it says 30 day trial expires.
In this case, is proscan 18.3.1 but I think version is irrelevant as I hit by this in earlier release, while trying to pickup a new update during the 30 day time.
HTH