When setting up a used EX2200 switch we encountered the following error when performing a commit check:
{master:0}[edit]
root# commit check
mgd: unable to execute /usr/sbin/ffp: Bad file descriptor
mgd: unable to execute /usr/sbin/ffp: Bad file descriptor
error: foreign file propagation (ffp) failed
We checked the file system and those binary didn’t exist so we’re assuming that the previous owner messed with the file system and ended up removing some critical stuff. Probably why they sold the switch. Simple enough resolution.
Resolution: Reinstall JunOS (in this case we upgraded it)