Mail refuses to show mailboxes
This followed loss of the program when it literally disappeared from the MacMini. A copy of it was copied back to it from an external drive and it seemed to worked okay for a couple of days albeit the contents of some of the mailboxes was incorrect, which I corrected by replacing them from a backup. Strangely one of the 5 mailboxes is resorting to a mailbox that never existed but has the files in it that are needed. So I copied all those files and pasted them into the sent mailbox that is now the only one Mail will show.
I did not find MAIL on the original installation discs that came with the Mini. I plan to upgrate to Tiger to conform to family computers for common use of video conferencing. Will installing that cure the problem, or must it be fixed before the upgrade?
Mac Mini G4 1.43 GHz; 1 GB memory, Mac OS X (10.3.x)