I have error 99 in my camera canon 400d

Error 99 is a general fatal error.
which includes the problems above mentioned by Q4SteveB but also many others.

It can be caused by a dicky shutter, problems with the CF card interface.

If cleaning and trying a different lens has not worked. Not definitive but as a rule of thumb...
If it letting you take one picture then giving error 99.. and the picture is saved to the card (but may just be black) this is most likely the shutter needs replacing..

If it takes a picture and gives error 99 but there is no picture on the card or the picture is 0KB its a CF interface problem.

If you get an error 99 when you plug in the USB its a USB interface error, you can try a different cable but unfortunately in most cases if another lens or cable wont work it needs repair

Had this problem before found this guide online


1. Turn off the camera.
2. Remove the lens, battery, and CF card.
3. Allow the camera to sit without power for approximately 20 minutes.
4. Insert a fully charged battery, and turn on the camera.
5. Depress the shutter button as you would to take a picture.
Does the “ERR 99′ message appear? If it does, then the camera should be
serviced. If it does not, then please proceed to the next set of steps:
1. Turn off the camera.
2. Insert the CF card.
3. Turn on the camera.
4. Format the CF card in the camera.
5. Depress the shutter button as you would to take a picture.
Does the “ERR 99′ message appear? If so, then the CF card is the most
likely source of the issue. Try using a different card.
If the message does not appear, please complete the following steps:
1. Turn off the camera.
2. Clean the lens contacts by gently rubbing them with a pencil eraser
or soft cloth. Be careful that you do not let any debris fall into the
camera body.
3. Reattach your lens.
4. Turn on the camera.
5. Depress the shutter button as you would to take a picture.
If the “ERR 99′ message only appears when one particular lens is
attached, then that lens should be examined by a service technician.
If you see the “ERR 99′ with a different Canon lens attached, then the
camera should be serviced.

The Lens has a 'chip' in it .. the Camera 'talks' to the Lens using the copper (coloured) contacts you can see on the mounting ring.

Error 99 means tat the Camera has a problem .. maybe your contacts are girty ? (or broken ?) .. or maybe the lens 'chip' has failed ?

See if you can try it with another lens (perhaps take it to a Camera Shop and ask to try a Canon lens .. )