I followed your tutorial How do I fix a corrupted USB drive on OS X? and got the final message:

dd: /dev/disk2: Permission denied

Then I tried it with a sudo command and got the message:

dd: /dev/disk2: Resource busy

Do you have an idea how I can successfully fix my corrupted USB drive?

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1 Answer 1


You need to unmount the disk first. Before you can write to it using ddHere the command you need to run to unmount the disk:

sudo diskutil unmount /dev/disk2
  • Correct so +1, to be more complete: if the disk would've had multiple volumes using unmountDisk would be advised.
    – Montmons
    Dec 20, 2017 at 22:59
  • @Montmons To my knowledge there is no unmountDisk command, only unmount and unmountVolume. unmount should unmount the disk and all its volumes. But I could also be incorrect
    – Matthew
    Dec 20, 2017 at 23:22

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