So far, I can't get any of the obvious applications to open (a copy of) the original mail file. Word of course doesn't recognize it, TextEdit refuses it, and when I tried:
"formail -e -d -s inboxfile >> newinboxfile"
(substituting "Inbox" for "inboxfile" and "NewInbox" for "newinboxfile")
my console just sorta sat there for, well, a long time until I finally killed it off. There was a new file called "NewInbox", but it had nothing in it.
Any more ideas? I've got like 1.2GB of mail file sitting there mocking me. I'm sure MOST of it must be perfectly fine.