I have a Canon 700d and I got an error 20 saying "shooting is not possible due to an error".

I've tried multiple things:

  1. removing battery and reinstalling it

  2. removing sd card and formating it

  3. clean sensor, mirror from the menu

  4. remove and reinstall lens

  5. try different modes

but all the above trials are in vain.

I've also tried clicking the shutter button multiple times, but I can't hear any shutter moving.

Is this a shutter problem, and how can I solve it?


Error 20 is a mechanical malfunction with the shutter or mirror assembly. Your camera will need to be serviced.


After looking through many suggested reasons for error 20 I almost gave up. I started out with a water damaged 7D. I managed to get it to at least switch on after chasing the visible corrosion hot spots. Including the corrosion in the hot shoe and its micro switch.

As soon I had got it to switch on initially I ran it through my SPT software which reported a 220 error described as an "unusual shutter charge signal after recovery charge" and pointing to either an electrical or mechanical error with the shutter or mirror. I was then unable to get the back buttons to respond so I checked for further corrosion by removing the contacts from the back cover and checking and cleaning underneath them. It was after this that I had my first error 20 message. Taking out the batteries and leaving the body for a few hours I was able to get the back buttons to respond. In fact I would get as far as half way through the set-up menu before error 20 would kick in.

On switching on and operating the shutter button it was if the shutter motor was jamming. In desperation I pulled out the shutter motor and replaced it with a spare I had from a 5D MkII. Then on putting in a new and freshly charged generic main battery one day, I got as far as fully setting up the start-up menu and firing off 4 shots even with the flash operating before the dreaded error 20 returned. This made me think that although error 20 is attributed to either a mechanical shutter or mirror problem, this could not be so in this instance.

Anyhow, in the meantime I had acquired a 7D with some minute sensor blemishes but otherwise fully operational. Again in sheer desparation (hate opening up a working body) I thought I would swap the main pcb's of each and lo and behold error 20 disappeared altogether. Instead error 20 transferred to the newer 7D acquisition!! I had considered trying a replacement main board as well as a DC/DC board and bottom board as a (expensive) trial and error exercise. But having a board already, this motivated me to give it a try at least. I have now a replacement used board in the mail and hopefully will end up with two fully operational 7D.

I am still trying to figure out what part the main PCB has in all this. I have a suspicion that the FPC from the mirror side has a corroded socket on the main board which is not easily visible to the naked or magnified eye. There was corrosion at this spot but I tried very hard to clean it away thoroughly. Who knows

  • a water damaged circuit board that processes and communicates with electro-mechanical parts? i would imagine very little wouldn't you? i mean what good is any brain sending electrical impulses to mechanical parts anyway? how could pc board contamination affect anything? doesn't make any sense does it? Feb 15 '19 at 16:23
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    Upvoted for the effort of f.... really trying and sharing the information! Feb 23 '19 at 9:44

I tried following the "switch off" and the "remove battery" suggestions to no avail. What did work was to switch off, remove the battery, then switch on and leave turned on with no battery for 24 hours. It was as if the on-board computer was locked up. The TOTAL removal of any power for a given period appeared to reset the computer. Upon switching off and re-installing the battery, then switching back on, all started as normal and problem resolved. However, the fault has repeated itself after a couple of days. Although this fault was again resolved by following the same procedure, I do intend to have the camera examined, as clearly there is a fault somewhere. I hope this suggestion helps others in the same predicament. RRS.


Here's a full list of Canon EOS error codes. Here's a similar, less detailed list that includes suggested rudimentary solutions directly from Canon. If those suggestions don't work it is time to send the camera in for service.

Error 20 is indicative of a mechanical malfunction that has caused a disturbance or lockup that could likely be caused by the mirror, shutter, or aperture assemblies. But Error 20 does not necessarily pinpoint the shutter itself. Error 30 is a more specific shutter error that could be either mechanical or electronic in nature.

I've gotten a very few isolated Error 20 codes at random times over the years. Normally turning the camera off and back on has solved the problem. A time or two I've needed to remove and reinstall the battery and/or the lens to clear the code. Luckily that's always worked for me.

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