Currently, when an error occurs during preferences loading, we end up with either partial preferences loaded or no preferences loaded. Then on quit, whatever prefs we managed to load are written out to the preferences file. The original contents of the file are thus lost.
It would be better to back up the preferences file if an error occurs during loading.
Implemented in r7817.
Closed in the released version 3.5.3 of OmegaT.
Didier