SD card failure

Hi chaps, I took a few snaps and popped the card into a usb 'reader' that's stuck into a usb 'hub' that's connected, of course, to my iMac. As I just wanted a quick look at the shots I opened up DPP, highlighted the days images and went to the edit window and DPP froze ! - I restarted the programme (DPP) and got a disc unreadable by this computer message, tried a different card reader (the one in my Canon printer) and got the same message, put the card into the camera and the camera now didn't recognise it, as the shots weren't very important I re-formatted the card and the 'format' worked OK. At last, you're thinking, I get to the question ... what might have corrupted the disc ? ... DPP ? ... and should I risk using this disc again (ie is it now 'corrupt') and if, in future, I transfer from disc to my hard-drive, will I avoid the problem. many thanks Roger

rogertb wrote in post #13448384
... what might have corrupted the disc ? ... DPP ? ... and should I risk using this disc again (ie is it now 'corrupt') and if, in future, I transfer from disc to my hard-drive, will I avoid the problem. many thanks Roger

By "disc", I assume you mean "card". Personally, I wouldn't trust the card again. The failure may have been a glitch that will never appear again, but I'd still toss the card.

As to what caused it, it could be a number of things, including pulling the card from the camera while it was still being accessed, a failure in a critical part of the FAT, a glitch from plugging the card into your reader...

I suppose the "safest" way to transfer pics is to connect your camera via the USB cable and not pull the card at all. But that can also be slow. I'd just chalk it up to a card failure, get a new card, and continue on as before.

Thanks Tom, I think that's what I'll do - regards Roger

As to what caused the failure, it's indeed possible that you pulled the card too soon. But not many people are THAT eager. Likewise, a glitch on plug-in is extremely unlikely.

It's far more probable that a bit of the card went bad--and from your description, it's probably the bit that stored the FAT (I'll gloss over the technical details unless somebody asks me).

Here's the good news: all flash cards have spare memory inside, and when a bit of memory goes bad, it's automatically marked "never use again" and replaced with some of the spare. So when you reformatted it, you almost certainly "repaired" it.

To be absolutely sure, you could put the card in your USB reader and copy a bunch of random pictures to it from your computer until it is completely full. Then copy them back to a different (scratch) folder. If the copy-back works, you've just proved that the card is fine. Delete the scratch folder, format the card, and you're on your way. (On the other hand, if the copy/copy-back process fails at any point with an error other than "card full," I'd trash the card.)

Thanks Geoff for your, obviously, knowledgable answer and for your soltion/test for future soundness. I have decided though not to take a chance and as it was only purchased a few weeks ago I'll return it and probably buy a SanDisk which I've heard are very reliable.

best Roger