Well, my 40D died on Sunday will shooting a soccer match. I got a Err99 and it would not do anything. Remove batteries and it cleared but the error returned when I tried to take the first shot. When I got home, I removed the grip and put a battery in the camera, changed the compact flash card and changed lenses. Same Err99. Canon said send it to them.
It sounds like something in the mirror assembly because it would make to slow clicks and then give the error. It seems like the mirror assembly has been a problem for some. Any idea how common the problem is? Is it a known flaw in the camera that has been fixed or do you get the same design back and just hope it doesn't happen again?
Good thing I kept my 20D.

