Canon 20D - Err99
 

May be this is of interest to 20D users (or 10D, D-Rebel users, I don't know).

Recently I experiencend an Err99 on both of my 20Ds. The manual states, that this could happen when you use a third party lens. But in both cases I had genuine Canon glass on the cameras.

Here is what happened: the battery grip I use on both bodies was not tightly secured. The screw that goes into the tripod socket had loosened during shooting and this probably caused a power surge. So I tightened the screw and secured it with some - well, sticky tape, of course. No more Err99 since then.

Ah, what would we do without sticky tape!

Good to know. Thanks for posting this.