MacOS – How to fix a broken recovery partition (remove it) when repairing it is not possible

macospartitionrecovery

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.

Best Answer

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.

Related Solutions

MacOS – How to create or recreate a Lion recovery partition

First, open a Terminal.

Status before:

$ diskutil list
/dev/disk0
  #:                       TYPE NAME                    SIZE       IDENTIFIER
  0:      GUID_partition_scheme                        *128.0 GB   disk0
  1:                        EFI                         209.7 MB   disk0s1
  2:                  Apple_HFS Macintosh HD            127.8 GB   disk0s2

Get Lion Recovery Update v1.0 (431.91 MB)

Mount RecoveryHDUpdate.dmg

$ hdiutil attach ~/Downloads/RecoveryHDUpdate.dmg

Extract data from RecoveryHDUpdate.pkg

$ pkgutil --expand /Volumes/Mac\ OS\ X\ Lion\ Recovery\ HD\ Update/RecoveryHDUpdate.pkg ~/Desktop/RHD

Mount RecoveryHDMeta.dmg (in the RecoveryHDUpdate.pkg package)

$ hdiutil attach ~/Desktop/RHD/RecoveryHDUpdate.pkg/RecoveryHDMeta.dmg

Run tool that will finally resize current partition and create recovery

$ ~/Desktop/RHD/RecoveryHDUpdate.pkg/Scripts/Tools/dmtest ensureRecoveryPartition / /Volumes/Recovery\ HD\ Update/BaseSystem.dmg 0 0 /Volumes/Recovery\ HD\ Update/BaseSystem.chunklist
Creating recovery partition: finished

Status after:

$ diskutil list
/dev/disk0
  #:                       TYPE NAME                    SIZE       IDENTIFIER
  0:      GUID_partition_scheme                        *128.0 GB   disk0
  1:                        EFI                         209.7 MB   disk0s1
  2:                  Apple_HFS Macintosh HD            127.2 GB   disk0s2
  3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

Remove Recovery HD partition

Start by reading this document from Apple, which explains the recovery partition in Lion. From the article:

OS X Lion includes a new feature called Lion Recovery that includes all of the tools you need to reinstall Lion, repair your disk, and even restore from a Time Machine backup without the need for optical discs.

In short, if you remove this partition you'll need a Lion USB drive, or physical media to perform the actions described by Apple above.

To reclaim the space of the recovery partition follow the steps below:

Open Terminal.app
Run the commands below (omit the # and everything after)

$ diskutil list                                   # list disk partitions
/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.1 GB   disk0
   1:                        EFI                         209.7 MB   disk0s1
   2:                  Apple_HFS Nymeria                 499.2 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3 <---
$ diskutil eraseVolume HFS+ Blank /dev/disk0s3    # Erase Recovery HD
$ diskutil mergePartitions HFS+ "Nymeria" disk0s2 disk0s3  # Merge partitions / reclaim space

One thing to note here, you can only merge consecutive partitions. If you have disk0s2 and disk0s4 running diskutil mergePartitions HFS+ "Nymeria" disk0s2 disk0s4 will merge partitions disk02s2, disk02s3, disk02s4. Also, only the data on the first partition will be preserved when merging. As an example, if your Recovery HD is disk0s3 and your OS partition is disk0s4, merging using diskutil is not possible. Use extreme caution modifying your partition table, and I'd highly recommend taking a full backup before hand.

Best Answer

Related Solutions

MacOS – How to create or recreate a Lion recovery partition

Remove Recovery HD partition

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