Time Machine Saves My Bacon

If you see this on your Mac at startup, you might have a bad boot drive. (image courtesy of TRC Data Recovery).

In 2009, my wife’s iMac suffered a drive failure due to a bad logic board. While we were able to replace the drive, the data recovery was very expensive, as the drive had to be taken apart in a clean room and recovered piecemeal. While most of the data wasn’t that important, there were enough family photos that justified the expense. Since then, I’ve had an external Time Machine drive connected to her computer (just do it, I said).

Two weeks ago, while I was out of town, that 2009 drive stopped dead. It failed without any warning whatsoever. Of course, these things always happen when I’m out of town, but at least this time I was able to say “don’t worry, we’ve got everything backed up” (holding my breath).


Before I did anything else, I took the iMac over to my local Apple Store for a free diagnostic. I wanted to know if the problem was simply the hard disk, or something more serious. I made a Genius Bar appointment via the Apple Store App on my iPhone. Easy-peasy. I was greeted promptly, and within a few minutes we had the iMac connected to the Apple Store server and running diagnostics. The good news: everything checked out fine except the drive was bad. Ok, now I had a game plan.

I checked out drives from Other World Computing, and picked up a pair of Hitachi 1TB drives. Why a pair? because I figured I’d replace the Time Machine volume with one of equal capacity (the old drives were 500GB). Hard drives aren’t expensive. I think I paid $70 each for them. I also picked up the necessary tools to open the iMac… the hard part.

iMac Drive Replacement: Not for the Faint of Heart

I then proceeded to find instructions on how to replace a hard drive in an iMac. It’s not easy, but not impossible. You need suction cups, torx drivers, and a lot of patience. This task requires removing cable connections, and if you’re not comfortable with the thought of that, have it done by an authorized service center. It took me about an hour to open the iMac, remove the old drive, and install the new one. You’ve got to be really careful to put everything back together the way you found it and keep dust and fingerprints off the display.

Restoring the Drive

Now it was time for the moment of truth: booting the computer. I had the original system DVD that came with the iMac, and booted from it (hold down the “c” key during startup). So far, so good. From the installer utility menu, I found the Restore option, and it located the Time Machine drive. I followed the on-screen instructions and let it run. It finished in about an hour.

Not So Fast!

After the restore, I restarted the computer and crossed my fingers. Immediately, the computer went into a kernel panic. NO! I tried again. Same result. What happened? The system installer that came with the iMac in 2007 was OS X 10.5, and my restore system was 10.7.5. Apparently, there’s a problem trying to run a restore of system 10.6 or later (Snow Leopard/Lion/Mountain Lion) from a Leopard (10.5) system disk. So then what?

The Solution

It turns out that you can create a bootable system disk on a USB thumb drive. It took about 30 minutes to create the system disk on an 8GB thumb drive (fortunately I was able to do this on my computer). I took the thumb drive up to the iMac, and with it booted off the system DVD, I used the Startup Disk tool to select the thumb drive and hit Restart. Fingers crossed. The computer booted up and offered me a Lion startup screen. From there, I re-ran the Restore utility and waited about 2 hours for the restore to complete. Reboot. Chime. Happy iMac! Everything was right where it was left off, including open Applications and documents. The only thing we had to do was go through some old emails and clean up the mail trash/spam folders. Other than that, the iMac is back to normal.

The moral of the story is that drive failures DO occur, and often without warning. The only thing we noticed on the iMac was that suddenly it became unresponsive (spinning beach ball) and then would not restart. Fortunately, we had everything backed up and the Time Machine restore was really easy once I had the proper boot disk. My wife is happy, and the only inconvenience she was waiting for me to get back from my trip to fix things up.

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