An app, due to an unfixed glitch, keeps overwriting an important file

How to lock that file so that it cannot be overwritten ?

Have root. Don't have xposed


You can remove write permission on your file. You would need toybox (inbuilt in Android since v5.0) or busybox. Assuming you have toybox already, use these commands in a terminal emulator:

cd /data/media/0/DIR              # replace DIR with wherever your file is. E.g. if the file is in /sdcard/Download, then DIR should be Download, so that the whole command looks like /data/media/0/Download
toybox chown 444 FILE_NAME        # this would set read-only permission for every user in the system for that file. Change 444 to 666 to revert changes.
chattr +i FILE_NAME               # alternative to above command. This prevents writing as well as deletion of the file. Change +i to -i to revert changes.

If you're wondering why the commands are performed on file under /data/media/0, read the answer here from Irfan Latif.

  • 1
    Thanks. Your answer works fine. I used Busybox (playstore). In my Android 4.1 I didn't have to navigate to /data/media/0 before my dir – Lucas BS Jun 3 at 21:00

Solution 1: Move the file to another folder. Thus, the app won't have access to it and can no longer change it.

Solution 2: If the file can't be moved (maybe because you don't want to move it, or that the app needs to access it from that folder), change its permissions to read-only. Any good file manager should be able to do it. click on the file, select properties then remove the write permissions.

Solution 3: Use a terminal and make the file immutable as stated in the comment using the command:

su chattr +i /path/to/your/file

Bear in mind that the second and third solutions will work only if the filesystem accepts the change of permissions or flags.

  • Unfortunately, setting a few R-W flags with a file explorer was not enough (ES File Explorer in my case). The app (which uses the file, and needs it where it is, simply replaces it). – Lucas BS Jun 3 at 21:03
  • I didn't test your commands (They require Linux, everyone!). Having it, it probably works. – Lucas BS Jun 3 at 21:05

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