Mac hard disk recovery when macOS Recovery doesn’t work

One of the reasons I use Apple Macs instead of Windows is how easy, painless and simple Apple has made it to backup and recover data. Time Machine — the Mac’s data backup functionality — is dirt simple, it just works, and it couldn’t be easier to use. Whether you need to recover a single file, a whole folder, or restore an entire machine, Time Machine has you covered. And macOS Recovery, the Mac’s function to recover from hard disk crashes and/or replacements, leverages Time Machine to make that dirt simple — except when it’s not available because your Mac is too old. So how to get around that…

This saga starts with my old Mid-2011 27″ iMac. This machine served me well for years, but it’s been increasingly relegated primarily to dust collection, as it just started to feel more and more long in the tooth. A couple of months ago, I backed-up its data manually to keep only the stuff I truly wanted, and wiped its hard disk, upgrading to macOS High Sierra in the process. There it’s been sitting while I wonder what precisely to do with it.

The machine tests out pretty well with Geekbench 4; about the only thing not really going for it is its circa-2011 i5-grade processor, but on paper, even that’s not that much of a slacker. But a benchmark on its old-fashioned spinny-platter (albeit 7,200 RPM) hard disk showed both read and write in the 100 MB/s range. Compare that to my slow-processor MacBook Air with its ~650 MB/s writes and ~1,450 MB/s reads. I began to realize that the old iMac felt slow not because of the computer itself, but because of the hard disk bottlenecks.

Other World Computing (OWC) offers a wide range of upgrades for Macs, and even offers kits with the tools needed to get inside machines (like my old iMac) to do the dirty work. While clearly something only technically-inclined folks are likely to consider, having the goods available to DIY when you have the skills to do it is certainly welcome. And after browsing my options, I ended-up choosing a 500 Gig SSD upgrade kit that set me back about $215. I justified it by figuring-out the sorts of tasks that the old beast could be used for once it ran better.

The kit arrived yesterday. I’d already reviewed their instructional video a few times, and felt confident with the process, so didn’t hesitate to dive right in. Getting it installed was simple enough — getting macOS reinstalled? Well, not so simple.

Brief diversion: I’ve been down this road before with my 2013 MacBook Pro, whose hard drive I’ve replaced not once, but twice. It’s also where I’ve learned to appreciate Time Machine. The 2013 MBP has Internet-based recovery capabilities. Replace the hard disk with a bare metal drive, fire it up, follow the directions, and in under an hour, macOS has magically set itself up and restored your data from a Time Machine backup of your choosing. It was (twice) as if nothing happened other than the disk being bigger and better — everything was exactly as it was the last time I used the computer. I expected the same here.

What I failed to realize is that my Mid-2011 iMac doesn’t have the recovery capabilities baked-in. The assumption is that you’d insert a CD-ROM and recover that way, I guess. And that was where the adventure really began.

Apple doesn’t provide a lot of help on this topic. They mention a Recovery Disk Assistant, which you can run on another, working Mac — except it doesn’t work with newer macOS versions. More Googling; more unhelpful web sites and forum posts.

It was particularly disappointing that Apple itself provides nothing in the way of help around this. In the end, I found my answers on this web page on the Macworld UK web site. You can read it for yourself for the details, but the steps that pertained to me, more than halfway down the page were:

  1. From a working Mac, download a copy of whatever latest macOS version I could from my purchased apps in the Mac App Store. For me, that was El Capitan.
  2. Wipe and reformat some sort of external USB media, 8 Gig in size or better, and make sure the volume name was, exactly, “Untitled”.
  3. Open-up Terminal, and cut-and-paste the command line shown on the web page referenced above, and wait for it to complete.
  4. Connect that drive to my iMac, and restart it.

Voila, as they say. That enabled macOS Recovery to run — from the external disk. At that point, it was a matter of following directions in a process already familiar to me.

Once El Capitan was installed, I could do the High Sierra upgrade from the App Store.

In the end, it wasn’t the one hour process I was used to, but it was not that painful, and I now have an upgraded, nearly 8 year-old computer that — while not directly competitive with a current-generation iMac — certainly has enough horsepower to be useful.

The disk benchmark shows read and write both now in the 600 MB/s range, which is not as speedy as, for example, my early 2015 MacBook Air, but certainly orders of magnitude better than what it was.

With this boost, the old beast should make a terrific testbed for my technology reviews, as well as serving as a creative workstation for casual Adobe Photoshop, Adobe Illustrator, and other miscellaneous such things. And initial tests indicate it’s great for that.

Not bad for what I’d still describe as an “old” computer.