My Canon powershot s400 camera won't read memory card

SD and SDHC cards have a slide switch along one edge. The position farthest from the metal contacts locks the card, protecting it from writes. The position nearest the contacts unlocks the card.

For your model camera, the problem is likely that your camera's internal clock battery has worn out. But Canon will repair this free of charge, including free shipping. Please see the following link for more info:

http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=223&modelid=8777&keycode=2112&id=27465

I get a memory card error everytime I insert a memory card. They are not locked and I have tried 4 different memory cards and nothing works. How can this problem be fixed?

The clock button battery inside the camera has expired. Canon will fix this for free (or if you want, will send you a replacement battery with instructions on changing it out). Read the following recall advisory, then contact Canon at 1-800-OK-CANON:

http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=223&modelid=8777&keycode=2112&id=27465

The little internal button battery that keeps track of time is going dead. Canon will fix this for free on your model camera regardless of warranty status. Here's the link to the info:

http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=223&modelid=8777&keycode=2112&id=27465

On the old Powershot S400, this error was caused by a dead internal "clock" button battery. Fixing it required simply replacing the battery. But before you attempt to do that, would first suggest trying a different memory card.

Check your memory card to see if its locked!

Solution:
1 set date to 31-12-2030 23h59 and switch camera off.
2 wait two minutes, day will be 01-01-2003 and camera asks you to set the date
3 take away memory card
4 set the date to today
5 insert memory card again
Now your error should be solved.
Sucess, Jonny

Both I and my son have IXUS 400's bought about 3 years ago with this problem. Reformatting cures sometimes for a short time but basically both cameras are useless. Neil

Well there is a known problem witht eh CF memory design, i hope this is not your problem but it may be. Take your camera into a well lit area or get a small flash light. Open the memory door and peek down inside the camera and look at the pins inside the camera. Are they all uniform? does any look bent or out of place? there should be 2 uniform rows no pins should be missing or out of place. If they are you have a connection problem. This is one of the issues with this memory format and its why they have changed the design to SD. This is common with people who remove the cards alot and use a reader over time the card and the slot becomes warn and its very easy to bend pins because the card isnt sliding in smooth. If this is your problem (a few bent pins) you may have to take it in for service or try and fix it yourself. Ive read about people using a mechanical pencil. Remove the lead and the pin slips right into the top and you can carefuly move it back. Hope this helps!