Unlocking is also easy. Using the Family Trees → Manage Family Trees… Menu command brings a selection window with all your existing Tree database files. If any row has a Lock icon, double-clicking opens a dialog asking if you want to break the lock.
But… more importantly in regards to your other annotation…
using a three-fingered-salute (Ctrl-Alt-Del) to ‘force a quit’ does not do the proper housekeeping needed when closing a database.
You COULD run a bunch of tests & repairs. You will be a lot more confident that your Tree database is undamaged if you make a backup, create a new blank Tree & import (restore) the backup. This rebuilds all the underlying structure. (It is good to do this process everyone months anyway. It tests your backups & optimizes that database.)