My Canon 40D has an "error 99" when shutter button is pressed.

Here is the list of things I've tried:

  • change the battery
  • shoot without CF card
  • shoot without lens

In all cases, the error comes back, systematically, and it is impossible to shoot again or do anything else (even picture preview mode doesn't work). A reboot is necessary, but the error comes back as soon as I try to shoot again.

I am aware of the other posts about this problem but it seems that in those cases the problem was the lens (see here).

(According to some readings on the web, I found that "error 99" can mean a lot of different stuff...)

Does anyone know how to solve this problem?


1 Answer 1


The Canon Err 99 is essentially their version of the Blue Screen of Death and simply rebooting may not fix it, but simply cleaning the contacts and rebooting is pretty much all you can do. It's their "unknown cause" error. To quote from the Canon Europe website description of the 99 error code:

This is a general error that can occur because of several different reasons.

The basic troubleshooting steps you can follow are:

  1. Turn the camera off and detach everything from the body that can be connected to it: card, lens, and or flash, to eliminate the possibility of the error being on the card, the lens, or the flash. :) You can use the body cap that came with the camera to protect the body from dust.

  2. Remove the battery.

    2a. If you have an older model body with a separate clock battery, remove that, too. (60D and later XXD, and 450D and XXXD models don't have one).

  3. Clean the contacts on the camera body (many pointers on how to do this on the Canon website).

  4. Leave the batteries out for an hour to overnight, to dissipate any residual charge, or alternatively, turn the camera on, or press the shutter button. (See: the How to "reboot" your camera sticky on the POTN board).

  5. Replace the battery (or batteries), turn the camera on, and see what happens.

  6. If the camera is fine at that point, then add back your card, and test again. Then add back your lens and test again. Then add back your flash and test again. If the error occurs, you have at least isolated it to the probable cause: body, lens, card, or flash.

Sometimes you can't fix it. Sometimes, the camera really is broken and requires service. When I got an Err 99 on my old Rebel XT, none of this (or replacing the clock battery) worked; the power board had shorted and needed to be replaced. Sometimes, them's the breaks.

  • \$\begingroup\$ After step 4 I'd try the same again with any clock battery removed as well, replacing it with a new one and cleaning the contacts. I think this battery also maintains shot count and several other things but that might only be true in older models. It's also worth leaving it some time with the batteries out. \$\endgroup\$
    – Chris H
    Commented May 12, 2016 at 18:35
  • 1
    \$\begingroup\$ @ChrisH, I didn't include it because the newer bodies don't have a separate clock battery (my guess is they're using an internal capacitor), but it's a good thoughts. Updated with a 2a) to remove it along with the main battery, and a note on leaving out for some time. \$\endgroup\$
    – inkista
    Commented May 12, 2016 at 19:13
  • \$\begingroup\$ I've got a 40D but couldn't remember. \$\endgroup\$
    – Chris H
    Commented May 13, 2016 at 5:54

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