Password Depot automatically creates a backup copy of your databases in the folder "Documents\Password Depot\Backups".
You can restore them by opening the backup copy with your master password and then saving it again:
1. Open the database manager (CTRL + ALT + O)
2. Scroll down in the left bar and choose Backup Files
3. Select a backup copy and click Open.
4. After you have opened the file, save the file as *.pswe (via Database > Save as).