Apple Watch Ultra 4 randomly restarts

At this point, I’d contact Apple. Since you already unpaired it and set it up as a new watch, you’ve ruled out quite a bit. I wouldn’t keep repeating resets.

Make a note of the approximate times when it restarts and ask Apple to run diagnostics. If it keeps rebooting with a clean setup, I’d want them to check the watch itself rather than assume it’s an app or setting.

I also wouldn’t assume the European version has anything to do with it.

i'm experiencing the same issue only when using the iMessage app on the Ultra 4, but the issue i think it's fixed because Gemini told me to reboot both devices (Watch Ultra 4 & iPhone) and since then no more random rebooting !

I didn't swap the watch at the Apple Store i just keep it, i know it's a software issue

Apple Support run a diagnotics on the watch so far no hardware issues

TuMiDaj wrote:

Right now, the biggest mystery for me is whether this is an actual hardware defect or just a software bug. If it's a hardware issue, I'm planning to return it immediately. Since I bought it online in the EU, I have a statutory 14-day return window no questions asked, and I'll definitely use it.

Has anyone found any concrete info or official acknowledgement on what exactly is causing this? On the other hand, if it's strictly a software issue, I really don't mind waiting for the next watchOS update. I just don't want to risk the return window closing and ending up stuck with a defective unit.

Neither Apple or Apple Support will confirm. It’s just not how Apple prefers to operate with potential customer service issues.

If the watch goes past 14 days, your watch will be replaced with another watch. But the replacement is just that. It will not be a retail product. Some users are not entirely satisfied by the warranty at that point.

Since Apple and Apple Support do not participate in these communities your best path forward would be to contact Apple Support.

If you’re in the US, please call  1-800-MY-APPLE, or outside the US, consult the support articles below. In Canada, call 1-800-263-3394.

Contact Apple for support and service - Apple Support

Genius Bar Reservation and Apple Support Options - Apple

Sorry for your customer experience. Your best path forward will be to consult with Apple Support. Purchasing a product outside the region it was intended to work in may produce unexpected results.

Sometimes the best opportunity is to return the done with the Apple 14 day return period. If you purchased from another merchant please review their return policy.

A workaround fix has been posted on reddit at https://www.reddit.com/r/AppleWatch/comments/1wmsccl/workaround_for_apple_watch_series_12_ultra_4/

I just noticed your partial analytics report. Most likely cause is a corrupt app. Have you unpaired and setup as new with no third party apps?

It could also have been a thermal issue which can be common because of third party apps, Siri and Apple AI on a new compatible watch. Lots of background activity going on.

Hardware can’t be ruled out, but it’s always a possibility. It could also be corrupt firmware. I’d consult Apple Support or wait for engineering.

Just my interpretation.

It’s a known issue. Lots of posts on here and elsewhere where people have the same issue. Report it here. Feedback - Watch - Apple

Try a forced restart. Press and hold the Digital Crown and side button at the same time. Hold them both until the white Apple logo appears and then release. Try it for a few days. If it happens again, you’ll need to unpair and the re-pair your iPhone and Ultra Watch.

The other option is to return the Ultra Watch during the 14 day return period. If you purchased your watch from another merchant consult their return policy.

Just pointing out all options. Some people don’t like the idea of a brand new (relatively expensive) product having issues. The option to return is a preferred remedy for some owners.

Like you, I prefer to wait for updates, but that’s not everyone’s preference.

I have had about six or seven of these since release day. I thought it might be a hardware issue with the particular one I had, so I have ordered another one, and will be returning the first one. 

And I am on the latest software as well (I updated it on setting it up on release day).

I've accessed the diagnostic log in the Watch app in General/Diagnostic Logs, and exported it to my Mac, and searched through the log with TextEdit. But there isn't any panic in the log, and I also cannot find any ANE either. So unsure what this means.

I had my ultra 4 replaced and extracted the same timeout issue on the neural engine from the panic files, which may indicate a software problem rather than a hardware issue:

That’s true, but underlying issue is it has to be reproducible. If engineering can’t reproduce the issue how do you determine the exact cause? Apple has two or three ways to reproduce. But hardware issues require a device that is actually malfunctioning. If no one goes to an Apple Retail Store with the issue how does Apple obtain an actual malfunctioning device?

When I was a Store Manager we’d actually get a directive from Apple Support to capture a new device exhibiting very specific reproducible issue. The item would be FedEx to Apple engineering next day. This is why it’s vital Apple Support is made aware of the issue.

it's a software issue, i have the same issue as well, just wait for the newest update coming soon

i hear iOS 27.0.1 is coming soon as well