My main system is bootable but disk utility says it needs to be repaired.

I can start disk utility from Live-USB which can verify my OS X partition but gives errors on checking the whole disk. The error is "unknown file system" - but it appears only after it found the main file system.

I guess my (hidden) recovery partition might be broken, since I cannot boot into it. Maybe this is the cause for disk utility to bring the error.

I would like to repair the recovery partition or at least delete it. I know there are tutorials of how to create a new one.

  • What is the model of mac being used?
    – bret7600
    Commented Feb 2, 2017 at 1:50
  • iMac 2010 mid i7
    – bomben
    Commented Feb 2, 2017 at 2:18
  • For future reference, it is possible to use Internet Recovery by pressing Option-Command-R, giving the same result, but without having to create a live USB.
    – bret7600
    Commented Feb 2, 2017 at 13:27

1 Answer 1


I removed my partition with

$ diskutil eraseVolume HFS+ Blank /dev/disk0s3

which created a blank space.

I then also had to repair the disk in disk utility. Since then everything works fine.

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