I own a 128GB Micro SD card from Sandisk which I know is perfectly fine and healthy. It is formatted in exFAt and worked perfectly with my Samsung S5. Now I bought a Samsung S7 and I replaced the card from my S5 to my S7. Since I did that my S7 running on stock Samsung Android 7.0 shows a window I have to format the card before I can use it... Off course I didn't do that since there is very important data on it. So I put it into a card reader connected to Windows which detected it as perfectly fine. I ran "scandsk x: /f" on it from within Windows and it said the file system is healthy and did not have to be repaired. After I eject it from Windows and put it into my S7... Android reads and writes it perfectly fine again... until I reboot my phone. Then the format screen shows up again. This loop keeps on going infinite...

Android 7.0: extSD is corrupted -> Windows 10: checkdsk /f: card fine -> Android 7.0: extSD reads -> Android reboot -> Android 7.0: extSD is corrupted -> Windows 10: checkdsk /f: card fine -> ...

So anyone got the same issue and found a solution?


1 Answer 1


The Solution was simple after all, chkdsk told me the volume was fine when I did a (basic) error check [/f] but when I did a check for bad sectors [/r] it found tons of errors and repaired them. It took some time but now I have all my data back!

So if you have this problem with any sd card mounted for example as drive u:\ then run in cmd:

chkdsk u: /r /v

ps: format my card as fat32 was no option as it is 128GB and I would lose all my data.

  • 1
    If it had a ton of bad sectors it'll die completely sooner or later. Backup that data before it's too late. Sep 11, 2017 at 15:14
  • yes it did and you are right, more are showing up lately... I'm making a complete backup of the card and after will do a full format of the entire sdcard.
    – Kleajmp
    Sep 20, 2017 at 17:33
  • If you're constantly getting more broken sectors, not format can fix the card. The problem is not at logical level (corrupted filesystem) but on hardware level (weared down flash chips). The card firmware tries to hide the broken cells but once the damage is too high, you end up with errors visible to the operating system. Jul 9, 2019 at 17:30

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