Mountain Lion Upgrade Dependency

It is important to check that the recovery partition exists before performing the upgrade from Lion to Mountain Lion.  In testing the Gold Master (GM) release, I found that the installation will start and progress as expected until the system reboots into the installation boot.  At that point, it will fail and you will be caught in a perpetual loop if your recovery partition is non-existant.  Always make sure you have a recent backup before performing the upgrade or any of these steps.

Check first that the partition exists:

From terminal, “diskutil list” and look for a recovery partition.

$ diskutil list
#:                       TYPE NAME                    SIZE       IDENTIFIER
0:      GUID_partition_scheme                        *750.2 GB   disk0
1:                        EFI                         209.7 MB   disk0s1
2:          Apple_CoreStorage                         749.3 GB   disk0s2
3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

If you don’t see a partition named “Apple_Boot Recovery HD“, you will need to create it.

Steps to create the recovery partition:

  1. Download the Lion Recovery Update v1.0
  2. From terminal, mount the Lion Recovery Update disk image.
    hdiutil attach ~/Downloads/RecoveryHDUpdate.dmg
  3. Expand the package from the Lion Recovery Update disk image.
    pkgutil --expand /Volumes/Mac\ OS\ X\ Lion\ Recovery\ HD\ Update/RecoveryHDUpdate.pkg ~/Desktop/DelMe
  4. Attach the disk image for the recovery partition.
    hdiutil attach ~/Desktop/DelMe/RecoveryHDUpdate.pkg/RecoveryHDMeta.dmg
  5. Create the recovery partition and copy it into place.
    ~/Desktop/DelMe/RecoveryHDUpdate.pkg/Scripts/Tools/dmtest ensureRecoveryPartition / /Volumes/Recovery\ HD\ Update/BaseSystem.dmg 0 0 /Volumes/Recovery\ HD\ Update/BaseSystem.chunklist
  6. Verify the recovery partition is in place. You should see a partition labeled “Apple_Boot Recovery HD“.  You can verify it is functional by rebooting and holding the option key and booting into the recovery partition.
    diskutil list
  7. Finally some cleanup steps.
    hdiutil detach ~/Downloads/RecoveryHDUpdate.dmg
    hdiutil detach ~/Desktop/DelMe/RecoveryHDUpdate.pkg/RecoveryHDMeta.dmg
    rm -rf ~/Desktop/DelMe

Hopefully these steps will help prevent a bad upgrade experience.  I am not sure how common it is to find you don’t have a recovery partition.  In my case, I think it was because I restored my OS a couple times while testing the development releases.  Good luck with the upgrade!


1. How can I create or recreate a Lion recovery partition?


PistarinoNovember 4th, 2012 at 9:10 am

Hi, I do have an “Apple_Boot” partition type, but the name field is empty. Does my Recovery Partition exist? When I boot with “cmd+R” combination the Internet Recovery starts (it means the recovery partition boots if and only if I have an internet connection, even if I simply need to repair my boot disc with “Disc Utility”, and I have to wait a full download of something). I have already Mountain Lion upgraded from Snow Leopard.

MZA AdminNovember 4th, 2012 at 12:40 pm

Would it be possible to upload the output from “diskutil list”? It might be possible to confirm the existence of the Recovery Partition. The need for Internet connectivity might be to confirm your license before performing a new install or a repair. What version specifically are you running 10.6.x?

PistarinoNovember 4th, 2012 at 1:15 pm

I have ML 10.8.2, and the download lasts too much to be a simple license check (the progress bar needs about 40 minutes to complete on my DSL line);
the diskutil list output follows:
0: GUID_partition_scheme *320.1 GB disk0
1: EFI 209.7 MB disk0s1
2: Apple_HFS MacBookPro HD 318.4 GB disk0s2
3: Apple_Boot 1.4 GB disk0s3

JimNovember 4th, 2012 at 9:06 pm

I have seen that issue too and I agree that it seems to download the entire installer. I found an article for creating a USB drive for re-installation and repair. Perhaps that would give you the flexibility you need.

PistarinoNovember 5th, 2012 at 2:01 am

Ok, I’ll give a try. Thank you for your feedback!

Mac App ZoneJuly 14th, 2014 at 3:55 pm

Helpful if the recovery partition is corrupted.

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