Random Lockups Still Plague macOS Sierra and High Sierra

Malwarebytes discovered Fruitfly malware for Macs

TMO editors and some Apple customers are reporting random macOS lockups, especially after an extended period in a screen saver.

One file from the Cosmos screensaver.
One file from the Cosmos screensaver.

In my own experience, macOS Sierra was the most stable version of macOS for my 2013 Mac Pro. It solved a major graphics freeze issue that was not in the OS the Mac Pro shipped with, Mavericks, but was rampant in Yosemite and El Capitan.

High Sierra

After installing High Sierra on the 2013 Mac Pro, there was an initial email glitch which I wrote about. “Adventures With the macOS High Sierra Install.” Other than that, High Sierra looked very stable. I had 20 days of continuous uptime—much of it with the default screensaver “Shell” kicked in.

I used that screensaver because, in Sierra, it appeared that the more stressing screensaver “Cosmos” would lock up my Mac Pro after about 6-12 hours.  I mistakenly thought that the simpler, built-in screen saver would exempt me in High Sierra. It did not.

About a week ago, that simple screensaver started locking up the High Sierra Mac as well after running for just a few hours. Symptoms:

  1. Full cursor/mouse control.
  2. All apps frozen in place and unresponsive.
  3. Keyboard unresponsive.

The only fix is to use the power button, shut down, wait a minute, then restart. Mercifully, the High Sierra system comes up quick and clean with no boot spinner.

Work Around

I’ve had just one lockup out of the blue. All the rest have been with the screensaver active. So I no longer use a screensaver. Instead, here’s what I do when stepping away:

  1. Apple Menu > Lock Screen.
  2. Turn off the display power.

Since invoking that technique, I’ve had no more lockups. Another TMO staff member reports similar success with that method.

A Wider Problem

The problems I’m having with this 2013 Mac Pro are not restricted to me. This Apple forum discussion cites the same lockup problem on another user’s 2013 Mac Pro. One user got a response from Apple support.

I have just heard back today (October 16, 2017) from my Apple support contact who has confirmed that:

Computers locking up is a known issue that is affecting many users who have upgraded to High Sierra.

As such, research will continue and it will be addressed in a forthcoming operating system update.

Clearly, 10.13.1, released October 31 and 10.13.2, released December 6, have yet to address the issue.

In addition, two TMO staff members have told me that they have experienced this kind of lockup in Sierra on very late model MacBook Pros. So High Sierra doesn’t seem to be the only culprit.

What to Do

If you’re having this lockup problem with a screensaver active:

  1. Disable all screensavers. Try the Lock Screen approach I described above.
  2. Make sure System Preferences > Security & Privacy > Privacy > Analytics is turned on. That way, Apple gets crash data from your machine and can better analyze the problem.
  3. Describe your experiences here in the comments for all the rest of us to learn from.
High Sierra System Prefs
High Sierra System Prefs

5 thoughts on “Random Lockups Still Plague macOS Sierra and High Sierra

  • TMO you rock! you saved me over $2,000+!! >>> I have a late 2012 iMac 27″. Ever since I upgraded to Sierra >> etc etc >> now to Catalina, I’ve experiences the ever-so-frustrating unexplained lockups. My system would go into screensaver mode and then mysteriously, and without pattern, lock up. Screen goes dark, System totally unresponsive – even to the hard power down. The only fix for me was to unplug my machine, wait 5-7 minutes ( I determined less than 5 would not work reliably) and then power up. Our machine is in pristine condition and sees super light usage so this was a mystery to us. I’ve spent several hundred dollars on Apple service – SMC reset, wiped HDD, replaced HDD, replaced all DRAM, and now even replaced the system board. Nothing fixed this. I was just about ready to write a nasty-gram to Tim Cook and stumbled on your article. Your workaround, the disable screen saver and lock Mac up with dark screen has resolved my lock ups!! What would happen within an hour now has not happened for 4 days! Thank you TMO! And now Apple…pls fix your OS….

  • Yep, I have a mid-2011 mac mini running Sierra and frequently (maybe once a week) I see that screensaver bug after long periods (overnight or long day). Always wondered what was the issue as I turn off the monitor when not using it and then when i turn it on I either have no video or frozen screen with no trackpad/keyboard input noticed. Only option was the power off. Actually, had to do that last night after getting home from work and mini had frozen. I will have to try turning screensaver off (I use the Dream Aquarium Screensaver just because I liked the scenes (and cheaper than the real one I had). I had chalked the problem up to a 7yr old computer that has been upgraded (memory,SSD,2nd SATA hd).

  • Another High Sierra issue seems to affect MacBook Pros with discreet GPUs.

    There are several discussions in the apple forums for this, I have noticed it on my early 2013 Retina MacBook Pro, at times I get a massive 2fps using either the discreet GPU or the intel HD4000 onboard graphics. At times, Photoshop is completely unusable and apps such as predictwind and websites such as windy.com, no chance of any smooth animation.

    The only fix seems to be to reinstall Sierra where you will get much faster graphics (normal), it’s as if High Sierra doesn’t implement OpenGL/opencl or metal 2 on a large proportion of laptops. The affected machines all are compatible with High Sierra too.

    Is Apple sure High Sierra is ready to be out of beta testing?


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