Bugs & Fixes: How best to restore an OS X Lion drive
If you ever need to restore the entire contents of an OS X Lion startup drive, or just perform a reinstall of the OS, you’ll find that there are numerous ways to accomplish these tasks. In fact, there are so many permutations, that I began to lose count after awhile. Trying to figure out the best method for your situation can get a bit tricky.
If you’ve traditionally used a backup utility such as SuperDuper or Data Backup to create a mirrored backup, you can still do so. Both of these backup utilities have been updated to work with Lion. Restoring a drive from the backup, assuming that Lion’s Recovery HD partition remains intact and functional, should work essentially the same as if you were running Snow Leopard.
You can also restore from a Time Machine backup. To do so, begin by booting from Lion’s Recovery HD partition (by holding down the Option key at startup and selecting Recovery HD). From here, select the Restore From Time Machine Backup option. However, as Dan Frakes explains in the linked article: “To use this feature, your Time Machine backup must be a complete backup that includes all system files.”
Rather than maintain a full mirrored backup, you may have a backup of everything except what Lion installs. In this case, you can erase your hard drive, reinstall Lion, and then restore from your backup. To accomplish this, boot from Recovery HD and select Disk Utility's Erase option. Next, select the Reinstall OS X option. This will reinstall OS X 10.7.0; assuming it is successful, you will still need to update to OS X 10.7.1, or whatever newer version is out at the time. Finally, restore your remaining data.
If you are only concerned about corrupt system files, you may be able to skip a restore of your data and just reinstall Lion. To do this, you again start up from the Recovery HD partition and go directly to the Reinstall Mac OS X option.
All of this gets still more complicated if you have one of the new Macs that come with OS X Lion preinstalled (the 2011 MacBook Air and Mac mini). The version of Install OS X Lion available from the Mac App Store will not install Lion on these Macs. These Macs have their own separate version. They even have a separate update to Mac OS X 10.7.1. In such cases, you’ll have to rely on the Recovery HD option to reinstall Lion.
Reinstalling OS X 10.7 via Recovery HD requires an Internet connection, as the installer has to both download OS X software and verify your computer’s eligibility. If you want to reinstall Lion without the need for an Internet connection, you have two main alternatives.
The first is to set up a bootable Lion install disc. To do this, you’ll need a copy of the Install Mac OS X utility from the Mac App Store. One complication here is that the Install OS X utility is moved to the Trash as part of an update/install to Lion. If you plan to use it again, save the application before it gets deleted. If this advice is coming too late, you can redownload a copy from the Mac App Store (by holding down the Option key when selecting the Purchases tab).
The other alternative is to purchase Apple’s $69 OS X Lion Thumb Drive. With this drive, you’ll be able to reinstall or update to Lion directly without any need for an Internet connection. One caveat: If you go this route, you will not be able to later reinstall Lion via the Recovery HD partition. You will have to use the thumb drive again. It’s one way or the other, but not both.
If Recovery HD fails
A related set of possibilities comes into play if your startup drive is so hosed that you cannot startup from the main partition or from Recovery HD.
If you have one of the aforementioned 2011 Macs, you can attempt to repair your disk, and reformat or reinstall Lion via the Lion Internet Recovery feature—an option that “lets you start your Mac directly from Apple’s Servers.” For everyone else, a solution will typically require that you have an external bootable drive for emergency purposes.
One way to accomplish this is via Apple’s Lion Recovery Disk Assistant software. Use it to set up a flash drive (or other USB drive) with a Recovery HD partition on it. After booting from Recovery HD on this external drive, you can repair, erase, repartition, and/or reinstall Mac OS X on your internal drive. Make sure you create this external drive before disaster strikes, as Disk Assistant requires access to a functional Lion drive with a Recovery HD partition. Creating a Recovery HD partition via Disk Assistant may also fail if you have FileVault enabled at the time.
Once again, the 2011 Macs that ship with Lion represent a special case. Apple states: “If the computer shipped with Lion, the external recovery drive (created by Disk Assistant) can only be used with the system that created it. If the system was upgraded from Mac OS X v10.6 Snow Leopard to Lion, the external recovery drive can be used with other systems that were upgraded from Snow Leopard to Lion.”
The other alternatives here are to use either of the Internet-free methods covered in the previous section.
Mirrored backup three-step
One final scenario. Suppose you have a full mirrored backup. Further, suppose you decide that you need to reformat/repartition your internal drive before restoring from that backup. Pre-Lion, all you would need to do is reformat and restore. Done. However, with Lion, a reformat typically means that you erase the Recovery HD partition. Restoring from a mirrored backup does not reinstall the Recovery HD partition. This means that a Lion restore requires an extra step: Reformat, reinstall Lion, and restore. The reinstall creates the Recovery HD partition.
What if you forget the reinstall Lion step during the restore process? You now have a drive with Lion installed (via your backup) but no Recovery HD partition. Can you add a Recovery HD partition at this point without having to start over? It would be nice, for example, if the Recovery Disk Assistant software could be used to create a Recovery HD partition on your startup drive, leaving the remainder of the drive intact. But it doesn’t work that way. Even if you created a separate empty partition via Disk Utility, prior to running Disk Assistant, it wouldn’t help—as the utility requires an existing Recovery HD in order to work.
As another alternative, reinstalling Lion by running the Install OS X Lion utility may re-add the Recovery HD partition (I have not yet confirmed this). I can confirm that running the Install utility will reinstall Lion 10.7.0 over an updated version (such as 10.7.1).
An ideal solution would be for third-party backup utilities to include Recovery HD in their mirrored backups. That way, a restore would automatically restore both the main and the Recovery HD partitions, saving you the extra step of reinstalling Lion. I have asked the developers of SuperDuper and Data Backup about this possibility. Both said that it is something they are considering for a future update—but there were no promises.
With the arrival of Lion, figuring out the best way to be prepared for a restore of your drive requires more planning than ever before. Some simplification may come with later updates to Lion. Until then, I highly recommend that you review all of the options covered here and determine which one(s) work best for you. Do it before trouble knocks on your front door.
A big thank you to Dan Frakes. Without his articles and his replies to my emails, I would not have been able to write this column.