Apple Watch Ultra 4 randomly restarts

Hi everyone,

I'm having a frustrating issue with my Apple Watch Ultra 4 (European version). It just randomly restarts itself throughout the day.

I'm on the latest update. The restarts are completely random and happen no matter what I'm doing – the screen just goes black, the Apple logo pops up, and the watch reboots.

I've already tried the standard fixes I found online:

Hard reset (holding the Digital Crown and side button).
Unpairing and setting it up as a completely new watch (without restoring from a backup).
Deleting third-party apps and turning off Background App Refresh.

None of this helped. Are any of you guys experiencing this issue on the latest software, or did I just get a defective unit? Any advice before I contact Apple Support for a replacement?

Posted on Sep 19, 2026 12:32 PM

Top-ranking reply

TuMiDaj Author

Level 1

31 points

Posted on Sep 20, 2026 1:20 PM

Thanks for the reply! You were right to suggest contacting Apple, as it seems I've exhausted all software troubleshooting.

I decided to dig into the Analytics Data on my paired iPhone and actually found a full Kernel Panic log corresponding to the exact time of the latest crash. It points directly to a hardware/firmware timeout issue with the Apple Neural Engine (ANE).

Here is the specific panic string from the log:

panic(cpu 1 caller 0xfffffff04b12bfd8): "ANE0: ANEHWDevice::ANE Timeout: channel=DataChainingCommand cmd=0x020C (CSNE_CMD_PROCEDURE_CALL_WITH_CUSTOM_BARS), waited=2020 ms, timeout=2000 ms, fANEFirmwareEnablePanicOnTimeout=1 unitTestMode=0\n" @ANEFirmwareManager.cpp:2974

And the faulty kext in the backtrace is: com.apple.driver.AppleH16ANEInterface

Has anyone else seen this specific ANE timeout panic before? I will definitely show this to Apple Support to speed up the diagnostic process, as it strongly suggests a defect with the Neural Engine chip rather than a rogue background app. I'll update the thread once it's resolved and I get a replacement.

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31 replies

Sep 23, 2026 1:47 PM in response to TuMiDaj

Watch os 27.0.1 came out today Sept/23/2026 has fixed this issue.

Apple Watch Ultra 4 randomly restarts