# How Do I Know My Memory Card Is Dying?

I have a 2GB SanDisk Extreme II (I think it's a II) CF card that I use as my main card in my Nikon D200. I normally shoot, take the card out, place it in a cheaper reader, and copy the pictures to my NAS using my iMac. I then format the card using the camera.

I've had the card around 3 years. I'm not exactly sure how many writes it's seen (I use another card on occasion so I could extrapolate from the number of total shutter presses reported in a RAW file).

The symptom that I'm seeing is that occasionally I'll fire my D200 in high speed and on the second or third shot an "Err" message will appear and all pictures taken since I started holding the shutter are gone. I doubt it is my camera as I've used my other card and it does not give the same error.

I tried formatting the card on my iMac using the disk utility and then reformatting it in the camera. This seemed to make the error go away for one or two sessions, but it is now back.

Is there a way to verify that the card should be replaced? What is the normal life span for CF cards?

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A replacement runs less than $10 ($5 for cheaper brands). Why not just do it? If the problem turns out not to be the cad, you have a spare card, which is good to have anyway. –  whuber Feb 11 '11 at 17:59
probably the card reader have the problem (combatibily issues with the camera write). The SanDisk have a long life, try to read the cart direct from your camera with usb to see if you read it or not. If you read it, then is compatibly issue with the way camera write, and card reader reads) I have same issues. –  Aristos Feb 13 '11 at 2:04
I ended up purchasing two nice Patriot cards from newegg.com. They were much faster than the SanDisk card. I let the camera rip in high speed, continuous shooting several times and it was able to write about 24 images with no problem to the card each time. I just tossed that SanDisk card. –  Mike G Mar 4 '11 at 14:20

The symptoms you have describe indicate a card you shouldn't trust any more. Bin it and buy a new one before you lose something important to you. The price of memory isn't high at the moment really so you might as well replace it.

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+1 for being 'penny wise and pound foolish.' Better to get a new card then to lose images. –  Jay Lance Photography Feb 11 '11 at 19:41
The 'penny wise and pound foolish' comment made me think. I'd easily spend as much money on a card reader or some other gadget to test this, but when memory cards are as cheap as they are there is really no need to fret over it. I'm not going to toss it, but grab a new one and verify that the issue disappears. If it does I'll toss the card. If it doesn't it may be that my camera will be off to Nikon for service. Thanks for enlightening me! –  Mike G Feb 14 '11 at 13:32

Since a card failure is catastrophic and the lost data is almost always unrecoverable (or you should assume it is!) -- and since it's most likely to happen in the field where you don't have many options, my policy on cards is simple:

I generally buy more, smaller cards rather than one larger. I typically buy a size or two below the largest generally available card. they're also a lot cheaper per megabyte than larger cards.

I always carry spares, never "one" card. These days, I carry 2 16 gig cards for my 7D (one in camera, one as a spare). I carry a half dozen 4Gig cards with my 30D since it's data requirements aren't as significant.

I always format the card in the camera before shooting. that also makes sure I don't start the shoot with the card half full and wonder where my space went.

I rotate my cards so they all get about the same amount of use, so you aren't wearing out one card while leaving the spare unused.

I always buy cards from major manufacturers -- I currently carry some from Kingston and Lexar. This is not a time or place to "save a few bucks".

I typically retire a card at 18-24 months just as a precaution. No sense pushing to failure.

The FIRST time I get a corrupted image or some kind of read/format error on a card, it's retired and I replace it with a new one. period. exclamation point. Once it errors once, I won't trust it again. If I get an error in the field, it goes in the pocket immediately for data recovery, no more images written to it.

And I have not had a card failure or data loss on a card in over two years. for what it's worth. (knock on wood).

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good advise. While I don't replace mine as frequently,I do use smaller cards rather than a few very large ones. After having 2 8GB Sandisks fail in sequence not a few months apart (the 2nd being a warranty replacement for the 1st, which was only a few months old) I've not taken to using 4GB cards exclusively with my D200. Sadly the only brand carried here of any name is Sandisk, or I'd carry a spread of brands as well. –  jwenting Feb 28 '11 at 10:26

Here's the system I used to answer that question:

1. mount the card in my mac
2. open console and have it viewing the system log
3. erase all it's contents. (from a terminal, rm -rf /Volumnes/CF\ Card/* )
4. write data onto it until it's full. (from a terminal, cat /dev/zero > /Volumes/CF\ Card/testfile )
5. when it stops with a "disk full" or "no space left on device" message, remove the test file (from a terminal, rm -rf /Volumnes/CF\ Card/testfile )
6. look at the console, if there are ANY IO errors, toss the card.
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or, save yourself some faffing about and bin it because it is already failing on a frequent basis... :) –  JamWheel Feb 11 '11 at 19:56
maybe... when I did that I was dealing with \$80 cards, and needed to be sure it was the card, and not something else. Turns out it wasn't the card, it was the mirror pivot in the camera... hit it several times at high speed and it jammed up. –  cabbey Feb 11 '11 at 20:39

Compact flash cards have wear-leveling schemes built-in, so that the pictures you take don't get written to the same memory cells every time. The MLC NAND memory used in these things is usually rated for 10,000 writes. You should be able to fill the card up completely every day for 20 years straight without wearing out the flash memory itself.

There are probably other ways they can fail, though. The contacts could wear out. The bonding wires inside the chip or the solder outside could crack. I think you've pretty much answered your own question when you point out that your other card doesn't give you trouble.

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