When is the last time you actually *restarted* your Mac? If you leave it
running all the time it never has a chance to do some necessary "house
cleaning" which can result in that type of behavior. It's a good idea to
shut down & restart at least once a day rather than continuously allowing
the Mac to Sleep when not in use.
Also, run Disk Utility - Repair Disk Permissions, then see if the problem
continues. Reply back with compete Office & OS version details if you need
further suggestions.
HTH |:>)
Bob Jones
[MVP] Office:Mac