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:
- Make sure you are up to date with Time Machine. I found an external drive works best for me, especially for a laptop.
- 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.
- Restore your machine using the up to date Time Machine copy.
- Once the restore is complete you will have recovered your machine but not replaced the Recovery HD partition.
- Download or get hold of an OS X Lion installation disk and run the installer.
- Run a minimal install of OS X and let the machine reboot.
- 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:
- 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.
- 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.