05-28-2013 05:19 PM
There's a bit of felt-like materials. Try to squeeze the two-halves together before screwing it back in. It helps to have another person helping you.
05-28-2013 06:14 PM
Well I called Canon support because I had a shoot - they said it doesn't actually screw in and out - that there is a flange that's supposed to catch - anyway - they couldn't help me except for the info - after I hung up I noticed there was a noise like something was loose so I shook it down and low and behold it seemed to catch - the gap is not totally closed but it seems solid and is not moving - go figure ...