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Cyclic Rendundancy Error Reading Compact Flash Card

John Hollenberg

New member
I just got back from a backpacking/photo trip. Three of my compact flash cards (two 2 GB Sandisk Ultra II, one 4 GB Sandisk Ultra II) were fine, but the fourth ( 4 GB Sandisk Extreme III, naturally) had CRC errors one 3 of the files. The Extreme card was formatted in Canon 1DS. Altitude was up to 9,000 feet, temperatures as low as 20 degrees. Would any of these cause a problem, or do I have a bad card?



Asher Kelman

OPF Owner/Editor-in-Chief

Welcome back in one piece.

Have you tried any data recovary software yet? I use Picture Rescue by Prosoft. That is excellent. Also PhoptoRescue by datarescue.com
Also tried "MediaRecover"

If that is not working perhaps try gentle drying by putting the chip near an oven with it on vey low, such that you wouldn't get your hand hurt. It would be about 100 degrees F.

This would dry out the card if that was an issue.

Let me know what's going on!

Where are you located, BTW, if you were in L.A., I'd have a go myself!


John Hollenberg

New member

Yes, I am in L.A. Tried to use Rescue Pro, but it was unable to read the card at all. Then I put it back in the card reader, got a message that it wasn't formatted!!! Fortunately, I had already copied all but the 3 files to a mirrored RAID. I determined by looking at the sequence that the 3 files probably weren't ones I wanted anyway, so just went ahead and reformatted the card.

Unfortunately, now I don't know whether I can trust this card. I put in a support request with Sandisk, so should hear something soon.

By the way, there was so much snow left and so many downed trees on the road that the last 8 miles of road to the trailhead was closed. We elected to hike an extra 8 miles each way and didn't see anyone for 4 days!


John Hollenberg

New member
Final resolution: formatted card in windows per Sandisk instructions. Then used RescuePro to look for files. After 30 minutes, I got a message that:

"Cannot read media (device: Windows drive H: (3.81 GB) LBA: 4305155, blocks: 1853)

When I select "Retry" I get the same error no matter how many times I retry.

"This can indicate a severe problem with the media or damaged card"

I am awaiting an RMA number to get a replacement card.


Mike Spinak

pro member

The Extreme card was formatted in Canon 1DS. Altitude was up to 9,000 feet, temperatures as low as 20 degrees. Would any of these cause a problem, or do I have a bad card?
I have taken many, many shots with a 1Ds and CF cards, at altitudes from 8,500 to 14,000 feet, and temperatures from around freezing down to 2 degrees Fahrenheit. I have never had this problem with a CF card, and do not think that these conditions cause problems for CF cards.



John Hollenberg

New member

Thanks for info. I didn't think this should cause a problem (and I, too have never had problems with elevations up to 14,000 feet), but wanted to be sure. Just received a replacement card from Sandisk, so apparently they agreed the card was defective. Now I am wondering if I should use a program to write and read the whole CF card, to make sure all the memory cells work before I start taking photos.


Ray West

New member

for peace of mind (if you are pc user with cf card reader) then I would format the card in pc, drag and drop a cardfull of data a couple of times, run chkdsk, just to test it a bit before I used it in the camera, then format it in the camera, of course.