when your sd card won’t format

I wanted to reclaim my Kingston 4GB SD card that had two partitions on it (70MB and 3.6GB), for use as a boot disc for my Raspberry Pi, but using the built-in partition manager (Disk Management) in Windows 7 and the SDFormatter that rPi.org recommends only enabled me to format or delete the smaller of the two partitions.

UPDATE: SDFormatter was version 4.0, and is actually the tool distributed by the SD Card Association. Official, but useless for this task.

I still don’t know why this was the case, and since I’ve now found a fix I don’t really care enough to figure out what the issue was (especially considering my searching for an answer brought me to many other people with the same problem, and not always reasons or reproducible results).

Frustrated with the lack of ability to completely wipe the card, I remembered the way I most commonly format SD cards — my camera. I had no idea if the internal “format” option would wipe all partitions on the card, but I figured it was a good hunch.

When I popped the card into the camera, it only showed space available for three photos — which tells me it was reading the 70MB partition. After formatting the card via the camera’s internal menus, the entire 4GB was available for photos.

I put the card back in my computer and confirmed that yes, there was now only one partition on the card, and it was alloted the entire space on the card.

So, a quick fix for the SD card partition problem: use your camera to format the card.

Apparently this is my answer to every SD card problem…

[FWIW, it was a Pentax K-x DSLR.]

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