SvA - 2026-01-04

There was a bug in unit conversion calculations between inches, points and centimeters which may have caused page size and margin settings to run off, and eventually cause an error as you got.
It already has been fixed in the code repository and will be included in the next release.

For now, the fix is, as you did. If editing these settings from the print settings dialog is no longer possible, the remedy is to restore a backup of the file PrintSettings in the Settings folder within OpenSong's document folder (or delete it and let OpenSong create a new one with default settings).