I have a Canon G10. When I removed and reinserted my sdhc card, I now get a message that the card is locked. This happens for every card I now insert, even though the lock switch is in the unlock position on the sdhc cards.

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.

This is a common problem with SD & SDHC type memory cards - and is easily fixed.

Remove the card from the camera and inspect the edge for a sliding tab and lock indicator.
You can see the tab & lock indicator on the left side edge in the picture of the front of the card above. Slide the tab UP - away from the lock position - as shown in the picture. The card is now able to be written. When the tab is in the lock position, the card may only be read.

Carefully reinsert the card into the camera - taking effort to see that the tab is not bumped / moved back into the lock position. You should be able to take pictures and have them saved to the card - without the locked message from this point on.

I hope this helps & good luck!

You didn't specify the type of memory card, so I assume it's an SD/SDHC 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.

It's not a SIM card, they only go in mobile phones.

You must mean the memory card. The G10 takes up to a maximum 8GB SDHC card, and like all SD and SDHC cards it has a locking switch which can accidentally be activated.

Look at the top of the card (i.e. label side up, clipped corner to the top right). Quarter of the way down on the left edge of the card is a tiny switch, fully forward (towards the electrical contact end of the card is unlocked, anything else can be locked.

If the switch is clearly in the locked position then slide it firmly until it clicks into the unlocked position. if it's already unlocked, slide the switch fully to locked and then fully back to unlocked until it clicks.

If that fails then try another unlocked card to see whether the fault is with the card or the camera.

There are several possible causes for "memory card locked", "memory card error", or "no memory card". Some include trying to use a 4GB SDHC card with an older camera made before SDHC format came out. Others include problems with the tiny slide switch on the side of the card, or the electrical contact switch internal to the camera. The problem may also arise from simple formatting problems if the card has never been formatted in the camera (note that this will also erase the card). Troubleshooting tips for this problem may be found at this link. By the way, if you're using 4GB or larger SDHC cards, they won't work with the SD400 as that camera was made before SDHC came out. Consider 2GB or less standard SD cards only. They're very inexpensive these days on Amazon..

I do not have a solution, but I do have same problem, or a variation of it: filled my ProSpec 2GB, removed it from my Canon G10 to insert a fresh card, then later reinserted the ProSpec to transfer photos to computer. Several tries, and no go. First time the camera display read "card locked"; I removed it and it was not locked, but I gently toggled the card switch back and forth anyway, then reinserted the card in camera, and the display read "card damaged". I then inserted the card into a card reader, actually several of them, and the computer did not recognize the card. So, I too am stuck.
ProSpec is a Calumet product, so I called a Calumet retailer (close to me in cambridge MA); the problem was new to them, and they asked me to bring the card by, so they could try opening it on their equipment, which I will do tomorrow, and I will let you know.
I do not think that I have ever had to format a card on a G10, and I would highly recommend that you not try formatting a card that has important photos. I believe that formatting always begins with erasing everything on anything.
Best, Jack Lueders-Booth [email protected]
PS - I cannot recall ever having experienced problems such as this with either Ilford HP5, or Kodak Tri X.

All SD (and SDHC) cards have a locking switch on them and this can be activated accidentally when handling the SD card.

Remove the SD card and slide the switch on it away from the lock position. If this does not work or if the switch is already in the correct position, then slide it all the way to lock and then fully back again.

If this fails then you have a faulty SD card and must replace it. Dirty electrical contacts do not result in a card locked message so you won't have to worry about those but as with all memory cards never touch the contacts unless they clearly need cleaning. Note that if you have to replace the memory card you can use regular SD cards up to 4GB and SDHC cards which start at 4Gb rising to 16GB maximum. The camera slows down when using SDHC above 8GB though.

I hope that you have found my answer to be of use and in return I ask only that you rate my answer.

First of all, the 4GB card will never be able to work in your camera. Check on its face. It likely says SDHC, and SDHC cards as this format came out after your camera was designed (I know it looks exactly like a normal SD card, but it's not).

Now the 2GB card should work with your camera as it is a standard SD card. Remove the card from your camera. Look on the side of the card for the tiny slide switch, and slide it to the other "unlocked" position. Reinsert it in the camera, and see if that corrects the problem.

If your SD memory card contains more than 1,000 images, the camera will display "Communication Error". Use a card reader (if available) to import your images into the computer, or see about having some CD's made at a photofinishing business.

Has this card EVER worked with your camera? Since you didn't mention the model number of the Canon, it's possible that you have a compatiblity issue here. Most 4GB SD cards these days are actually SDHC cards, which store memory differently (in sectors, like a hard disc drive, rather than bytes, like your main memory). All SDHC compatible cameras also support SD cards, but cameras sold before the SDHC standard was created will not support SDHC memory cards.

There's a chance that Canon has a firmware upgrade to solve this. You would have to look on the Canon USA web site for this, based on the model number of your camera.