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Reboot on a loop - 2019 MacBook Pro 16in

Hi, My MacBook suddenly restarted and it's now stuck on a loop. After entering password progress bars gets just after midway, fan blows and it restarts again.


I've tried:


  • Force shut and turn on again.
  • Diagnostics on Recovery mode. No issues found.
  • Start and restart from Safe mode.
  • Reset SMC.
  • Reset NVRAM/PRAM.
  • Reinstall macOS


Nothing has worked.


Problem Report gives this:

panic(cpu 4 caller 0xffffff7f8ddca983): GPU Panic: mux-regs 5 3 7f 1f 0 0 severity 3 WS-ready 0 switch-state 13 IG FBs 0 EG FBs 0:1f power-state 0 3D idle HDA idle system-state 0 power-level 20:20 power-retry 0:0 connect-change 0 : PowerPlay Failed to Initialize.


From what I can read, it looks like maybe I'm not the only one with this problem.

Any ideas, anything else I can try? Has anyone been able to resolve it?


Thanks, appreciate any help.


2019 MacBook Pro 16in

macOS Catalina 10.15.5

2.6 GHz 6-Core Intel Core i7

T2 Security Chip

Powerbook

Posted on Jun 11, 2020 3:47 PM

Reply
7 replies

Jun 15, 2020 1:16 PM in response to __Jupiter

Hello __Jupiter,


Welcome to Apple Support Communities!


I understand from your question that your MacBook Pro is unable to start up all the way. I can certainly help you with this!


I would refer you to this article: If your Mac starts up to an Apple logo or progress bar


It does, however, look like you have done all of these troubleshooting steps so I would reach out to Apple Support.


I hope this is able to resolve your issue. If you have any more questions or this does not resolve your issue, please reach back out on the thread!


Cheers.

Jul 9, 2020 4:07 PM in response to __Jupiter

About mid-June (2020) I've went to Apple Genius bar and was told it was a known problem and to wait for fix. Meantime turn off auto graphics switching in Energy Saver settings. Seemed to help at first, but now sometimes it takes an hour of futzing with crazy startup keys. Seems to boot safe mode reliably, but it's too slow that way. I've seen no acknowledgement from Apple or timeline for fix. I even see some related discussion threads being locked. A real scandal !

https://discussions.apple.com/thread/251301645 <--- locked

https://forums.macrumors.com/threads/16-mbp-gpu-panics.2221004/page-12

https://discussions.apple.com/thread/250905859?page=40

https://medium.com/@drdDavi/my-2019-16inch-macbook-pro-is-dead-59874018748f

Jul 12, 2020 2:15 AM in response to __Jupiter

You are definitely not the only customer with this issue. I have the same and have replied on other threads this morning.


I have performed clean fully formatted reinstalls of MacOS with SMC and NVRAM resets and it still has the issue straight into boot from that process, so it must either be a fundamental OS issue or a hardware issue. I wouldn't waste your time with those efforts as I have.


As it happens straight from a clean boot my feel is it must be a hardware issue, although onboard hardware diagnostics do not report a problem.


Apple support are refusing to replace the machine as they state is is a software issue when I call. The only offer is to take to a Genius Bar (significant disruption) but are not clear on what the options would be if I do.

Reboot on a loop - 2019 MacBook Pro 16in

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