A tip for reviving old flash memory cards


A neighbour dropped by with a digital camera he had misplaced for several years. It uses a Sony Memory Stick Pro card, a flash memory type I haven’t seen in a long time. He said the camera had lots of pictures, but each time he tried turning on the camera, it said “Insert memory card again” on the screen.

It took me plenty of searching to find an old card reader that could read such cards, but found one in the end. Unfortunately, it didn’t seem to work, i.e. no drive letter appeared and when I inserted the memory card, Windows Explorer would stop responding. I tried a few different cables, ports and then my laptop just to also rule out a bad connection, but go no further.

With the card reader still plugged in to my laptop, I started chatting away with them and after something like 10 minutes, I made one last attempt of unplugging and plugging in the card reader and after about a minute, the drive letter finally showed up. However, when I tried going in, of course Windows Explorer stopped responding. I then tried via the command prompt and was able to navigate into the DCIM folder.

After getting this far, I attempted to start copying the files to the hard disk with the robocopy utility and it spent a long time reading each file, sometimes 2-3 minutes. Roughly every 8 to 10 files gave a dreaded Cyclic Redundancy Check fail:


Anyway, at the rate it was going and 259 pictures in the folder, they decided to head off, leaving my computer to do its job and come back another day. To my surprise, when I came back an hour later, it had completed the copy with quite a number of failed files.

I decided to rerun the robocopy process and this time it copied all but one file, reading each file in 5 to 10 seconds compared to the several minutes earlier. With one final copy attempt, it successfully read that last file.

I do recall observing something similar in the past, but nowhere as severe as this card. I remember the card was extremely slow to read, but sped up during the copy process, giving an impression that the power was reviving the flash.

So for anyone who has an old memory card that does not show up or difficult to read, try leaving it in the card slot for an hour or two, then try accessing it again. :wink:


Sounds more like the repeated accesses were causing the card’s controller to initiate its defect management strategies, which remapped some questionable areas. The long-term stability of such a card is questionable, and since they are so cheap it would be risky to continue to use one for anything important.

Really, the handling of a failing memory card should be directed at recovering whatever is needed from it (if there is anything) prior to throwing it in the trash.