Seeing a warning stating "database or disk full" typically means your device is running low on storage and thus the app can't save your notes properly. You might also not be able to save any changes or even add new content as it will be deleted after input due to the low storage conditions.
In some cases, you can start the app but this message keeps appearing:
Internal Error: SQLite error 13 with
statement 'SELECT* FROM
sqlite_master LIMIT 1: database or
disk is full
Please go to your device Settings and check if there's a "Storage Full" message under your Apple ID. If so, please tap the message and see if you're in fact out of device storage. In that case, please follow the recommendations in the right-hand section to free up some space. Also try deleting any unused notes in GoodNotes and emptying the Trash. See if the message is gone and the GoodNotes issue is also resolved.
If you still have lots of device storage despite the message, please try any of the following:
- Restart your device.
- Offload GoodNotes: Go to device Settings > General > iPad Storage > GoodNotes > Offload App. This will take quite a while. After that, tap "Reinstall App."
- Back up your device and restore it from the backup
- Contact Apple Support for further software/hardware support.