My MBP 2015 15" often hangs with the same sequence of events. First the fan starts rushing up to top speed, then the screen gets some lag, then becomes unresponsive, and then the whole thing hangs in this max CPU state indefinitely until powered off (you can't even move the mouse). I'd really like to be able to log what software is running so I can start to troubleshoot. I don't have to be using any app in particular to make it hang, and I can otherwise do CPU intensive work like video editing without problems. Any ideas?

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    I've known OpenGL apps to do that. idk how you could interrogate at Console-level, but keeping Activity Monitor open, sorted by CPU usage could be one way. iStat Menus too, with the GPU menu bar active could maybe let you glance at usage as it starts to ramp.
    – Tetsujin
    Jul 13, 2019 at 16:51
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    Show us a picture in activity monitor what the CPU usage is for all tasks. Also, can you measure external temperature of the case when this happens? Warm or cold might be something to correlate with this. Be sure you edit your post so all the details are in the body. The steps for kernel task are different from overheating from hardware from other...
    – bmike
    Jul 13, 2019 at 16:57
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    It's clear to me. The user doesn't know what to do. Not all user are tech savvy. Try Apple's support site. Suggest you pick what version of macOS you are using and post in the appropriate forum. discussions.apple.com/productsitemap.jspa. Jul 13, 2019 at 19:25
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    create a launch daemon to run. while :; do top -l3 >>/Users/mac/topperloop; sleep .5; done; You will need an account to see this post on how to create a daemon: medium.com/@fahimhossain_16989/… Jul 13, 2019 at 22:20
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    You could try dtrace. developer.apple.com/library/archive/technotes/tn2124/… Yes, it's out of date, but it's readable. Jul 13, 2019 at 22:38

1 Answer 1


I had the exact same issue on my MBP 2017 15", using it with external screens and Mojave 10.14.6. Turned out to be a bug with NightShift (documented here). Turning off NightShift solved the problem.

Maybe this will also help you.

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