3

Two crashes in one week.

First time, my macbook was in idle state, and I was not at the desk. I only noticed that the system restarted when I tried to log back into it. Here is the crash log from console:

Process:               WindowServer [133]
Path:                  /System/Library/PrivateFrameworks/SkyLight.framework/Versions/A/Resources/WindowServer
Identifier:            WindowServer
Version:               600.00 (564)
Code Type:             X86-64 (Native)
Parent Process:        launchd [1]
Responsible:           WindowServer [133]
User ID:               88

Date/Time:             2021-02-10 22:06:53.784 -0500
OS Version:            macOS 11.0.1 (20B29)
Report Version:        12
Bridge OS Version:     3.0 (14Y908)
Anonymous UUID:        BBF14B17-C2EC-E01D-AFDF-FE5E2D9304E5

Sleep/Wake UUID:       7563D56A-0A47-457B-B758-83193417162E

Time Awake Since Boot: 710000 seconds
Time Since Wake:       45000 seconds

System Integrity Protection: enabled

Crashed Thread:        0  Dispatch queue: com.apple.tcc.preflight.kTCCServiceScreenCapture

Exception Type:        EXC_CRASH (SIGKILL)
Exception Codes:       0x0000000000000000, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY

Termination Reason:    WATCHDOG, [0x1] monitoring timed out for service
Termination Details:   WATCHDOG, checkin with service: WindowServer returned not alive with context:
unresponsive work processor(s): WindowServer main thread 
40 seconds since last successful checkin, 4511 total successsful checkins since wake (0 induced crashes)
...    

The 2nd time was this morning, when I was working on my macbook, and suddenly, my mouse was frozen:

Process:               WindowServer [68647]
Path:                  /System/Library/PrivateFrameworks/SkyLight.framework/Versions/A/Resources/WindowServer
Identifier:            WindowServer
Version:               600.00 (564)
Code Type:             X86-64 (Native)
Parent Process:        launchd [1]
Responsible:           WindowServer [68647]
User ID:               88

Date/Time:             2021-02-17 09:11:56.499 -0500
OS Version:            macOS 11.0.1 (20B29)
Report Version:        12
Bridge OS Version:     3.0 (14Y908)
Anonymous UUID:        BBF14B17-C2EC-E01D-AFDF-FE5E2D9304E5

Sleep/Wake UUID:       B380A623-51A8-4067-981B-5664B5FE5B44

Time Awake Since Boot: 890000 seconds
Time Since Wake:       1800 seconds

System Integrity Protection: enabled

Crashed Thread:        0  Dispatch queue: com.apple.tcc.preflight.kTCCServiceScreenCapture

Exception Type:        EXC_CRASH (SIGKILL)
Exception Codes:       0x0000000000000000, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY

Termination Reason:    WATCHDOG, [0x1] monitoring timed out for service
Termination Details:   WATCHDOG, checkin with service: WindowServer returned not alive with context:
unresponsive work processor(s): WindowServer main thread 
40 seconds since last successful checkin, 185 total successsful checkins since wake (0 induced crashes)
...    

Never had this kind of crash with High Sierra, Mojave or Catalina. It has been happening since my macbook was upgraded to Big Sur.

Is there any possible fix?

Update: Another crash after my mbp was upgraded to 11.2.2

Process:               WindowServer [137]
Path:                  /System/Library/PrivateFrameworks/SkyLight.framework/Versions/A/Resources/WindowServer
Identifier:            WindowServer
Version:               600.00 (570.7)
Code Type:             X86-64 (Native)
Parent Process:        launchd [1]
Responsible:           WindowServer [137]
User ID:               88

Date/Time:             2021-03-16 13:03:14.038 -0400
OS Version:            macOS 11.2.2 (20D80)
Report Version:        12
Bridge OS Version:     3.0 (14Y908)
Anonymous UUID:        BBF14B17-C2EC-E01D-AFDF-FE5E2D9304E5

Sleep/Wake UUID:       9BE2C5FD-9A74-49FB-8A09-DD621680F654

Time Awake Since Boot: 110000 seconds
Time Since Wake:       15000 seconds

System Integrity Protection: enabled

Crashed Thread:        0  Dispatch queue: com.apple.tcc.preflight.kTCCServiceScreenCapture

Exception Type:        EXC_CRASH (SIGKILL)
Exception Codes:       0x0000000000000000, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY

Termination Reason:    WATCHDOG, [0x1] monitoring timed out for service
Termination Details:   WATCHDOG, checkin with service: WindowServer returned not alive with context:
unresponsive work processor(s): WindowServer main thread 
40 seconds since last successful checkin, 1507 total successsful checkins since wake (0 induced crashes)
...
5
  • 1
    Does this still occur if you update to macOS 11.2.1?
    – pion
    Commented Feb 18, 2021 at 1:44
  • @pion Oh, 11.2.1 has come out? I didn't know that. Usually the new os update would undergo an evaluation by company IT before it is released for use. Hopefully, the update could solve this problem.
    – Qiang Xu
    Commented Feb 18, 2021 at 14:32
  • @pion Another crash today after my mbp was upgraded to macOS Big Sur 11.2.2.
    – Qiang Xu
    Commented Mar 16, 2021 at 17:30
  • Can you please share the full crash report via www.pastebin.com?
    – pion
    Commented Mar 16, 2021 at 17:41
  • @pion Here you go: pastebin.com/McKaAXtn
    – Qiang Xu
    Commented Mar 16, 2021 at 18:02

2 Answers 2

2

Well, this one is puzzling. At first glance, it looks like something is trying to record your screen, and when WindowServer is requesting access, that request is getting timed out and causes WS to be terminated by xpc. Since from your description it doesn't sound like you're trying to take a screenshot/screencap, I can only theorize on possibilities:

  • You have Screen Sharing or Remote Management enabled in System Preferences -> Sharing and someone is trying to view your screen.
  • You have software or malware installed that takes screenshots/caps at certain times.
  • You have certain Accessibility features enabled.

None of the above should, in general, fail in the way that you're seeing, though. So you can check your settings in System Preferences and disable sharing & accessibility features as a test, but that would be a workaround at best, not a root cause & fix. (The malware possibility is there, too, but I'm always hesitant to go down that route until we've ruled out more benign causes.)

It should be noted that Big Sur has been a very buggy release and a lot of errors in particular pertain to WindowServer, so my suspicion is that what you're seeing is not at all your fault.

Here are things to try:

  1. System Preferences -> Sharing: Disable Screen Sharing and Remote Management, if enabled.
  2. System Preferences -> Accessibility: Disable any accessibility features you may have enabled.
  3. System Preferences -> Security & Privacy -> Accessibility: Disable all apps and share a list of them in your question.
  4. System Preferences -> Security & Privacy -> Screen Recording: Disable all apps and share a list of them in your question.
  5. If steps 1-4 don't help, the next time this happens, capture a sysdiagnose after rebooting from your crash and we can try to dig into your logs. You can do this either via the sysdiagnose command in Terminal or by pressing and holding the ShiftControlOptionCommand keys together and while holding these keys pressing and releasing the period . key.
9
  • Thanks for helping debug the crash, pion. Nothing in the list for items 1 ~ 3. For item 4, Scroll Reverser, VMware Horizon Client, and zoom.us are listed in System Preferences -> Security & Privacy -> Accessibility. Microsoft Teams and zoom.us are listed in System Preferences -> Security & Privacy -> Screen Recording. Not sure if I should clear the above two lists, since these applications are essential for company work.
    – Qiang Xu
    Commented Mar 18, 2021 at 23:46
  • By the way, I have just upgraded to 11.2.3. Will see if the crash would happen again.
    – Qiang Xu
    Commented Mar 18, 2021 at 23:49
  • 2
    That’s unfortunate. You may be stuck with these crashes until Apple fixes the underlying issue. We can still continue the investigation with step 5. I would encourage you, after gathering the sysdiagnose, to file a bug report with Apple. Let’s continue after you test with 11.2.3.
    – pion
    Commented Mar 19, 2021 at 0:02
  • 1
    Just filed a bug report.
    – Qiang Xu
    Commented Apr 28, 2021 at 0:39
  • 1
    @QiangXu I have the exact same issue :( Were you able to figure it out? I also noticed that for me the crashes tend to happen when I'm plugging my MacBook in or unplugging it. Commented May 9, 2021 at 7:29
2

This is an over-sized comment, because I don’t have the solution either.

I came across this bug yesterday, and I checked the crash reports. There were five crashes related to WindowServer, forming a crash loop (i.e. crash -> reboot -> log-in -> crash). Some of them are similar to the one in the question; their Termination Details field mentioned “unresponsive work processor” as the crashing context. Other crashes mention (formatted for readability)

is_alive_func returned unhealthy: WindowServer initialization not complete (post IOKitWaitQuiet)

instead. Remarkably, for all crashes, the stack trace of the crashing thread starts with

0   libsystem_kernel.dylib          0x00007fff204c82ba mach_msg_trap + 10
1   libsystem_kernel.dylib          0x00007fff204c862c mach_msg + 60
2   libdispatch.dylib               0x00007fff203697a0 _dispatch_mach_send_and_wait_for_reply + 530
3   libdispatch.dylib               0x00007fff20369bba dispatch_mach_send_with_result_and_wait_for_reply + 50
4   libxpc.dylib                    0x00007fff202421a8 xpc_connection_send_message_with_reply_sync + 238

The line following XPC (cross-process communication?) library varies from com.apple.LaunchServices to com.apple.HIDPreferences, so I suspect that something is wrong with the XPC library.

Note that the hex number (address of the method?) is different from OP, but it’s probably because of macOS version (I’m iMac at 11.6.1); the method names fully match, and offsets mostly match.

Another note: the crashing thread in the question is always com.apple.tcc.preflight.kTCCServiceScreenCapture, but my experience was different. Only one of my reports crashed at this thread. Others crashed at com.apple.main-thread. I suspect that the screenshot is only one way to trigger this bug.

2
  • I haven't had the crash for quite a while. Maybe because of the continuous upgrades. Currently, my mbp sits at macOS Big Sur 11.6.1.
    – Qiang Xu
    Commented Nov 10, 2021 at 13:31
  • I met another crash with the same pattern. This time the crashed thread is com.apple.tcc.preflight.kTCCServiceListenEvent. Commented Nov 22, 2021 at 7:23

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