I'm getting the Err 20 on my Canon R5 sometimes after I turn it on. A lot of times it happens after the camera has been sitting for a period (like overnight). I shut the camera off and turn it back on again and it works fine.
Online search says it's a shutter issue. I remember seeing more threads about this years ago but can't seem to find them.
Is this indicative of a failing shutter? Or something else?
I had the same ERR 20 problem daily on a R7 with only a few thousand shutter cycles. It worked fine for hours after power cycling so I suspected an internal software problem and updated the FW, reset to factory defaults, and let it set for 30 minutes with the battery and lens off. One of those things fixed it, as I've not had an ERR 20 for many months. If those measures don't work, you'll need to send to Canon Service for a shutter replacement.
