I have a 32GB micro SD card, and some of the apps I use state that they have permsisions to modify sd card memory. I have a lot of personal files on my card, and the other day, some app, I don't know which one, had practically wiped out over 15gs of files from my card!

How can I block apps from wiping out my sd card? I don't see what possible good can come out of an app that can wipe out all my personal files. I backed up my pics when a guy at work told me an app had re-formatted his SD card. Sure enough, the same thing happened to me. I was able to back up my files BEFORE it happened, but how can I prevent this from happening again?

  • 1
    I was curious if you had a chance to discover which app did this?
    – Daniel
    Mar 1, 2011 at 22:44

3 Answers 3


I've never heard of an app that formats the sdcard. The permission to modify the sdcard is so the application can "read/write" data to the sdcard.

If you have an app that formats your sdcard, I would report the issue to the developer, plus to the Android Market.


SD cards are almost always formatted as FAT, which means that the OS cannot set filesystem permissions. In other words, you cannot protect individual files. And you can only protect the SD card as a whole by not installing apps that access it.

I recommend frequent backups and testing out new apps thoroughly, possibly by using another SD card with unimportant or backed-up data on it.


There is an rsync in the market, which I use to backup my sdcard to my home server routinely (via its Tasker integration). From there, its a simple matter of adding it to the existing backup system.

rsync itself can also be configured to keep backups.

finally, if you have a rooted phone, I suppose you could format your sdcard as ext4, or partition it to also have an ext4 partition. Then you'd be able to use file permissions. Of course, you'd need ext4 drivers to use USB disk mode, so pretty much you'd have to use Linux.

You must log in to answer this question.