Hello! You should be able to change it via the Registry under:
"HKEY_CURRENT_USER\Software\Monothetic\Beacon\Screenmanager Resolution Height_h2627697771"
and
"HKEY_CURRENT_USER\Software\Monothetic\Beacon\Screenmanager Resolution Width_h182942802"
Make sure you hit the "Decimal" button and then enter the values you wish to use.
To make sure this doesn't happen in the future, can you let me know the following:
- Which resolution you're trying to use
- The native desktop (default) resolution of your monitor