I always remember to empty my "deleted mail" folder but forgot to empty the folder where all mail "sent" is in and now I have a year's worth of sent mail.  I get an error when I try to delete more than one at a time.   What's the trick?  I really can't see myself deleting them one at a time.  They go back to June 2009 and there are hundreds.
The actual emails all say: Message cannot be found
The contents of this message cannot be found.
And when I try to delete more than one at a time I get: Unknown Error has Occurred.
				
			The actual emails all say: Message cannot be found
The contents of this message cannot be found.
And when I try to delete more than one at a time I get: Unknown Error has Occurred.