I just bought from eBay a Kingston 32GB microSDHC that was advertised as defective. The seller said that there could be formatting problems or with transfer of large files.

Unfortunately, when I got it, it was a total mess.

  • My Nikon camera doesn't read it at all (OK, maybe it doesn't support 32GB)
  • My Linux laptop doesn't mount it: can't read superblock
  • The same laptop refuses to mkfs.msdos because it failed whilst writing reserved sector
  • The same laptop, under Windows, doesn't read nor format the card
  • HTC HD2 mounts the MMC, allows me to write via USB, but is unable to open the just written files

OK, folks, now you would say I would have to go through Paypal complaint... that's not that easy. I consciously bought a half-price card that was known to show some defects, and Paypal complaints take time.

Obviously, I can't accept somebody sold me a completely use-less computer decoration. So I'll keep it as last option.

My question is

Do you know a way, under either Linux or Windows, to thoroughly scan, test and possibly repair memory cards, even if I have to lose some percentage of space because of bad sectors?

If I can keep at least half of the card intact it would certainly be fine. I used to do broken sector marking with hard disks in the past.

I almost forgot:

MONSTR:/home/djechelon # fsck /dev/mmcblk0p1 
fsck from util-linux-ng 2.17.2
dosfsck 3.0.9, 31 Jan 2010, FAT32, LFN
Read 512 bytes at 0:Input/output error

Try with the official SD card Formatter. If that doesn't help and you have no problems with your card readers, then I'd say there's no fix for the card.


Don’t wait too long for the last resort since you only have 45 days to issue a complaint from the time of purchase.

What I would try in your situation, is to use a program that can access a disk at a low level (HxD is a good, free one), and use that to open the disk (run with administrator privileges of course). Then select the whole disk and write 0’s to it. There are two points that would need to be taken into account for this.

  1. It could take some time. See if the program you choose already has a built-in wipe or block-write function instead of doing it manually, because it could be faster. Also, see if the program, has the ability to not update the display (you certainly don’t want to waste cycles watching the sectors flash by—believe me, the novelty wears off very quickly, then you’re left waiting).

  2. If there are indeed physical errors, then you don’t want to have to click Ignore over and over and over again, so make sure to click the checkbox for repeat this action for future occurrences or similar option. (The program may also have an option to set the default action to avoid prompting you at all.)

Once you have completely wiped every byte of every sector of the disk, you’ll have a fresh, clean slate and be able to format it, or at the very least know exactly what state it is in (read how bad the damage is).

You could also opt to use a disk-wiping tool, but it may or may not wipe every sector; it might just wipe based on existing disk structures, especially consumer ones.

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