iMac gpuRestart and then crash

Question

Created Apr ’21

Replies 3

Boosts 1

Views 1.5k

Participants 4

Hi all,

This has been bothering me for quite a while. Basically my new iMac (bought for a few months only) started to crash randomly. I went to the genius bar and they couldn't do anything to identify the issue, I tried reinstalling the OS and even reinstalling an older version of Mac OS as well, but still seeing this issue. Today it happened twice and below are the details:

Mac specs:

Code Block Model Name:	iMac
 Model Identifier:	iMac20,1
 Processor Name:	10-Core Intel Core i9
 Processor Speed:	3.6 GHz
 Number of Processors:	1
 Total Number of Cores:	10
 L2 Cache (per Core):	256 KB
 L3 Cache:	20 MB
 Hyper-Threading Technology:	Enabled
 Memory:	16 GB
 Boot ROM Version:	1554.100.64.0.0 (iBridge: 18.16.14556.0.0,0)
 Serial Number (system):	xxx
 Hardware UUID:	xxx
 Activation Lock Status:	Enabled

The DiagnosticReports around the time it crashed has a lot of files with .gpuRestart, e.g.: Kernel_2021-04-27-213412_Zhuzengs-iMac.gpuRestart

and file WindowServer_2021-04-27-213319_Zhuzengs-iMac.userspace_watchdog_timeout.spin in between.

The details of the the first gpuRestart file

Code Block Tue Apr 27 21:32:13 2021
Event:               GPU Reset
Date/Time:           Tue Apr 27 21:32:13 2021
Application:         
Path:                
Tailspin:            /Library/Logs/DiagnosticReports/gpuRestart2021-04-27-213213.tailspin
GPUSubmission Trace ID: 0
OS Version:          Mac OS X Version 10.15.7 (Build 19H1030)
Graphics Hardware:   AMD Radeon Pro 5300
Signature:           2
Report Data:
GPU Log Version: 1
Restart Channel: 18 VMPT
---THE STATE OF THE DRIVER---
AMDRadeonX6000_AMDNavi14GraphicsAccelerator state: ENABLED
 PCIe Device: [3:0:0], DID=0x7340, RID=0x47, SSID=0x219
 TotalVideoRAMBytes: 0x00000000ff000000 (4278190080)
Uptime 21:50:05.077572
[00] Channel: GFX, last reset at 0:00:00.000000
  CompletedTS = 0x005be078, SubmittedTS = 0x005be079
  SentTS = 0x005be078, sent at 21:49:00.896511, ScheduledTS = 0x005be079, submitted at 21:50:03.672539
   Wait for Channel 18, TS 0xef924
  PendingEvent: YES NumberOfPendingCB = 1, FirstPendingTS = 0x005be079, LastPendingTS = 0x005be079
    FirstPendingCB: ProcessID = 225, ProcessName = WindowServer, SubmitContext = Unknown (0)
      GPUAddress = 0x0000000431cef000, Size = 0x000001d3, VMID = 2
      ContentValidation = PASS
      Buffer range 0x0 .. 0x100:
      *c0012800  80000000  80000000  c0026900  00000081  80000000  40004000  c0026900

By searching online this seems to be happening to others as well but I failed to find a common fix for this. Any help would be hugely appreciated!!!

Answer 1

MVAMkt OP

Jan ’22

Are you using more than one monitor?

Answer 2

Liquanmin OP

Apr ’23

Have you solved this problem yet? I also ran into this problem.

Answer 3

kfiducia OP

7h

Confirming this is still happening with the identical signature, five years later — I think that's the important part.

iMac20,1 (27" 2020), Core i9, AMD Radeon Pro 5500 XT 8GB, macOS 26.6.2 (25G83), single internal Retina 5K display (no external monitor).

Same fingerprint as the original report in this thread:

Event:               GPU Reset
Graphics Hardware:   AMD Radeon Pro 5500 XT
AMDRadeonX6000_AMDNavi14GraphicsAccelerator state: ENABLED
Restart Channel: 18 VMPT
FirstPendingCB: PID = WindowServer
VM Protection Fault events. Count: 0

…which then cascades into:

panic(...): userspace watchdog timeout: no successful checkins from
WindowServer (2 induced crashes) in 120 seconds

WindowServer's main thread is stuck uninterruptibly (TH_WAIT|TH_UNINT) in IOKitWaitQuiet during re-init, blocked in AMDRadeonX6000 → IOAcceleratorFamily2 → IOGraphicsFamily. VM protection fault count is 0 and thermal pressure was Moderate, so this is a clean GPU hang on the paging channel, not a memory fault or a thermal event.

In my case the trigger is specifically the display-sleep power transition (machine at rest, internal panel only), which is a different entry point than the external-monitor reports but produces the same channel-18 VMPT reset.

This signature is documented on this same iMac20,1 / Navi14 hardware from Catalina 10.15.7 (this thread, 2021) through Big Sur, Monterey, and now macOS 26.6.2 — unresolved the entire time. Given that it has survived every OS generation, could someone from Apple confirm whether this is a known Navi14 driver issue or whether it indicates GPU hardware degradation on these units?

I'm filing this with Apple Feedback Assistant now, with a full sysdiagnose + the crash reports attached (regression / hardware question). Happy to share the FB number, additional stackshots, or the tailspin with anyone from Apple who wants to pull it.