The Curious Relationship Between an iMac and an Electrical Outlet

March 9, 2022

About a month ago, my iMac’s hard drive died (or so I thought).

I was working in my office when all of a sudden I heard a pretty loud zap-zap sound from the iMac. A moment later, it shut down. Dark screen. Totally off. A moment after that, it restarted itself, but during the startup process, the iMac went into “recovery” mode. Shit.

Recovery mode is basically where the iMac says, I’m dead. We need to start from scratch. It asks whether you want to reinstall the operating system fresh, or if you want to reinstall from a backup of your data.

I’m a pretty reliable backup guy, and I knew I had a complete backup from earlier that day, so I tell it I want to reinstall from a Time Machine backup.


Then it shows me a list of backups on the Time Machine/backup drive. I identify the most recent one from that morning, but when it asks where I want to install it … nothing. The cursor just spins and spins. It can’t find a hard drive to install on. This happened to me before with my Mac Minis, so I assume the hard drive is dead. Same thing that happened back then.

To the Repair Shop

So, I take my iMac to our only local Apple-authorized repair shop. I tell them the whole story with the zap-zap, the attempt to reinstall the backup, and how it couldn’t find a hard drive to do the reinstall.

They call me the next day and tell me the iMac started right up on their workbench. No recovery mode. No problems.

WTF, right?

I tell them I want a new HD anyway because I don’t trust that it will work here at home. So they take out the pre-installed hard drive and replace it with a faster/better SSD (I think?) drive.

This is Where it Gets Weird

A couple weeks later, the same thing happens in the middle of my workday — zap-zap, iMac dies, reboots into recovery mode, can’t find the hard drive, etc. Exactly like what happened before.

I resigned myself to another trip to the repair shop, but then I remembered that the iMac worked for them in their shop. They couldn’t replicate the recovery/startup problem I had where the hard drive wasn’t found.

I thought, What if I just move the iMac somewhere else in the house? Crazy, right? But it’ll only take five minutes and if it still doesn’t work, then I can remove the idea that my office is the problem.

So I unplug everything from my office and set up the iMac in our dining room. IT STARTS UP JUST FINE. How is that even possible???? A moment earlier in my office, the iMac was acting like its hard drive was fried and now it’s working perfectly.

The only thing I can think to do is try a different outlet. So I rejig my office a bit. I connect the surge protector that the iMac uses to a different outlet about three feet away — an outlet that’s on a different electrical circuit than the outlet I’d been using.


In other words, when the iMac gets power from one outlet, it’s basically dead — can’t startup, can’t find a hard drive where I can reinstall a backup, nothing. (By the way, this outlet currently has my turntable and an Amazon Echo plugged in, neither of which has ever had any problems.) But when the iMac gets power from a different outlet three feet away, everything works perfectly.

It’s been about 2-3 weeks since this discovery. At the risk of jinxing myself, everything is working perfectly. And I continue to be totally mystified about the curious relationship between my iMac and this particular electrical outlet.

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