Restore Settings From Backup
Go to Tools>Options>System, click Restore Files
Choose a previous day, when your settings were OK.
If no files are listed, click Choose Folder to select your original backup location
Filter for settings, tick settings.ini and then click the Restore button.
Close and reopen Packing Partner
If there is an error when you re-open, run the installer again:
Packing Partner 3.5.3.x install / update