Update: The iMac started shutting off randomly no matter what apps I was using and eventually it was happening multiple times a day. I figured that it was probably the power supply, which is known to cause issues for these iMacs. I ended up getting a replacement power supply with a repair kit. I used this iFixit guide and it took about 1.5 hours and was easier than I thought it would be. I’m writing this update from that very same iMac I didn’t destroy. So far so good.

Original post:

Even with the advent of file restoration on the iMac, there’s nothing more defeating than when your computer decides to randomly shut down seemingly for no reason.

That was happening to me a while recently on my 27-inch, Late 2012 iMac. Granted, I push it hard and run Adobe Creative Cloud and iMovie along with 75 tabs on two different Internet browsers, but it really shouldn’t shut down randomly. And when I push the power button to start ‘er up again, it doesn’t work. I have to pull out the plug for 10 seconds to reset the power supply.

I tested the power supply, set up several different surge protectors, bought a replacement power cord, and even a backup power supply to no avail, the thing keeps shutting down.

What gives?

I had noticed a while back it has trouble waking up from sleep, so I keep it on constantly and risk the monitor burning out (which it has already done once—thankfully when it was under warranty). It’s certainly starting to sound like the quality control is not what it used to be at Apple and that’s one of the reasons I’ve sold my stock in the Jobs-less tech giant.

The solution is more of a hack. I’ve narrowed the seemingly random outages down to the use of two applications in particular: Quicktime and iMovie. When I was doing screen recordings with that program and leaving it running, that’s when the computer would shut down. When I’m not using those apps, the computer operates fine and when I do use them, I make sure to quit them right after use.

If you have had trouble with the iMac power supply, let us know in the comments section below.