Restoring the recovery partition in Mac OS X Lion

July 20, 2012

by — Posted in Mac OS X, Technical Stuff

Time Machine on Mac OS X 10.5
Time Machine on Mac OS X 10.5 (Photo credit: juancabrera)

Recently I foolishly zapped the hard disk of my Mac, removing both the main partition and the Recovery HD partition.  I found that I wasn’t able to re-install Lion (or Mountain Lion) from disk or USB stick because the installer kept complaining about there being no recovery partition present.

Thankfully I had been using Time Machine on an attached drive so, after a lot of playing around, found the following procedure which might be useful to some if it ever happens to to you:

  1. Make sure you are up to date with Time Machine.  I found an external drive works best for me, especially for a laptop.
  2. If the machine will not start on its own, plug in the Time Machine drive and boot.  It will start up in the OS X installation running from the Time Machine drive.
  3. Restore your machine using the up to date Time Machine copy.
  4. Once the restore is complete you will have recovered your machine but not replaced the Recovery HD partition.
  5. Download or get hold of an OS X Lion installation disk and run the installer.
  6. Run a minimal install of OS X and let the machine reboot.
  7. OS X Installer will create the Recovery HD partition, reinstall OS X but keep your data and applications you recovered from the Time Machine backup.

The result is a recovered machine, with the Recovery HD back in place.  To make sure your recovery is as smooth as this, do the following now, so you are ready in the future:

  1. Create a Lion install DVD or USB image – buy it from the Mac App store and follow the many instructions on the web for burning the InstallESD.dmg file to a disk.
  2. Make sure you use Time Machine and before attempting any gymnastics on your computer make sure you’re up to date.

I hope you find this useful.

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