Canon 7D II Error 20


CR Pro
Mar 22, 2012
Err 20
Description: A malfunction with the mechanical mechanism has been detected.
Resolution: Turn the power off, then remove and re-install the battery. Then turn the power on again.

Last saturday doing sports photography my 7DII started intermittingly showing Err 20. I did power off and remove and re-install the battery but it occurred a few times.
I didn't find too much detail on the internet - mainly about the 7D.
It seems it could be the mirror box malfunctioning.

I was wondering if anyone had any experience with this error.
Is it the sort of error that becomes more and more common making the camera inoperable.
I still managed to take about 3000 photos so its not completely broken.

I don't know the shutter count but I'd expect its high.
It's led a busy life (even if I wasn't its biggest fan to begin with - once I accepted its limitations it was a workhorse)

I'm not sure whether to flog it to death or get it repaired.
Have I nothing to lose in flogging it to death at this stage - would I be causing any more damage from a cost of repair perspective.
I'm not sure then whether to get it repaired or not or replace it with something else.
Before mirrorless arrived the ideal replacement (expensive ) would be the 1DX II or another 7DII


CR Pro
Apr 3, 2013
Isle of Wight
Hi Hector.
I gather from ‘I have nothing to loose in flogging it to death’ that you are either shooting for fun or have a backup because it almost certainly will quit and permanently and it may not have a gradual worsening, I had my 40D quit completely without warning, battery out and back in would get one shot but nothing was captured, I think the fault was a dead shutter (but it might have been the mirror assembly) and it showed error 99 but I think it only had 1-9 and 99 unlike newer bodies!
Bear in mind that the mirror and shutter are the only mechanical systems in there, I know the knobs and switches could be considered mechanical but I don’t believe they are monitored
If you might regret a missed shot or only getting 300 instead of 3000 then you know the answer! ;)

Cheers, Graham.
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CR Pro
Mar 22, 2012
Thanks Graham,
Its sort of a sad feeling. I don't know if I got an early dud of a 7DII or whether its a good as it gets. I never loved it but it did a great job on sport.
It always looked more sharp through the view finder than the end result but it did capture good action.
Overtime I began to appreciate its 10FPS for catching action. It did take some memorable images.
Sad to see it starting to die.
I hoping against hope it was a once off and won't reoccur for another 200,000 shots :)
To get it repaired might cost half the price of a new one and something else might fail.
Decisions, decisions.
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Mt Spokane Photography

I post too Much on Here!!
CR Pro
Mar 25, 2011
I' suspect its the shutter or mirror box as well, if you use high shutter speeds, its pretty stressful on the components. Sensors also wear out with exposure to light, but unless you do a lot of video, that's unlikely to happen in less that 20 or more years, and even then, IQ decreases gradually as you get more dead or hot pixels and noise goes up.

I'd be inclined to have it repaired, and wait for a year to see if a replacement is announced. You should get your moneys worth for the repair cost in the next year. If repair cost is out of sight, sell it on ebay with faults mentioned and get a replacement. By getting a new one, that will prompt Canon to move up the announcement of a new model by at least 6 months:D
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Hi Hector. Had exactly the same on one of my mk2's. it was one of the first in the UK as i got it on pre-order so done just under 4 years at the end of August. It started at a Football match coming up with error 20, told me turn off check battery connections which i did 30 or so later it did it again then again etc. The error code 20 then changed to camera can not fire shutter or similar and just left a black screen. Sent it off to be looked at and back came an estimate for £400 + UK pounds as it needed a new mirror box + shutter box and would be fully serviced as well so had it done as the mk3 is not on the radar yet, just hope the other mk2 keeps going.
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