When setting an inaccessible path as a target in Options > File naming this can result in the file naming options not being accessible and even Picard crashing.

On my system this happens when setting the target dir to "/run/user/1000/doc/". os.statvfs("/run/user/1000/doc/") fails with a PermissionError when trying to determine filesystem limits. On https://community.metabrainz.org/t/file-naming-option-grayed-out/717872 a similar setting triggered FileNotFoundError (although it is unclear how this would happen, as _get_filename_limit searches for an existing path).

In a more general sense the make_short_filename function can fail getting filesystem limits (in _get_filename_limit) with either a PermissionError or FileNotFoundError. In this case it likely should try higher up the path.