Missing or corrupted database files

The Details may indicate file data (or the file itself) is missing, as in these examples:

mnt: cannot open /etc/default/filesys

The file /etc/default/filesys is missing. Restore it from backups.

Failed to remove export configuration for filesystem - the object instance filesystem does not exist

The file /etc/exports is missing. Restore it from backups.

Failed to remove mount configuration for filesystem

The file /etc/default/filesys is missing. Restore it from backups.