New Delhi: Apple has released watchOS 27.0.1 for the newly launched Apple Watch Series 12 and Apple Watch Ultra 4, addressing a bug that was causing some watches to restart unexpectedly during everyday use.
The software update comes shortly after the two new Apple Watch models went on sale on September 18. Users had reported random restarts while performing activities including editing watch faces, making calls, using Siri, opening Apple Maps or the App Store, and even during workouts. Complaints were reported on Reddit and Apple’s Community Support forums.
The issue appears to have been specific to the new 2026 Apple Watch models, and Apple has now issued a dedicated software update to address the problem.
watchOS 27.0.1 fixes random restart issue
According to the report, the problem was linked to a Neural Engine timeout. A command sent to the watch’s Neural Engine was expected to complete within 2,000 milliseconds but reportedly took 2,020 milliseconds in the affected scenario.
That small delay was enough to trigger a complete reboot of the watch. Apple has not publicly explained what caused the Neural Engine command to exceed the expected time limit, but watchOS 27.0.1 addresses the underlying restart problem.
The issue could be particularly disruptive because users reported experiencing restarts while carrying out important activities. Some reports indicated that watches restarted during phone calls and workouts, potentially interrupting ongoing activity tracking.
Update is only for Series 12 and Ultra 4
watchOS 27.0.1 is being offered specifically for the Apple Watch Series 12 and Apple Watch Ultra 4, which are the two new models launched by Apple in 2026.
Owners of older Apple Watch models do not need this particular update because the restart issue addressed by the release concerns the new-generation watches.
Apple launched the Series 12 and Ultra 4 alongside other new products during its September event. The Series 12 starts at Rs 56,900 in India, while the Ultra 4 starts at Rs 1,09,900. Both models went on sale on September 18.
No major security fixes listed
The watchOS 27.0.1 release appears to be focused on fixing the unexpected restart problem rather than addressing a major security vulnerability.
According to Apple’s support information cited by India Today, there are no CVE entries associated with the release. This indicates that the update is primarily aimed at resolving the software issue affecting the new watches.
For users experiencing random restarts, installing the update should therefore be a priority, particularly if the problem has occurred repeatedly during calls, workouts or while using apps.
How to update Apple Watch Series 12 and Ultra 4
Apple Watch users can install the update directly from the smartwatch.
To update from the watch:
- Open the Settings app.
- Tap General.
- Select Software Update.
- If watchOS 27.0.1 is available, tap Install.
- Follow the instructions displayed on the screen.
Users can also install the update through a paired iPhone by opening the Apple Watch app and going to General > Software Update.
Apple recommends that the watch have at least 50% battery remaining and be connected to Wi-Fi before beginning the installation.
What the new Apple Watches offer
The Series 12 and Ultra 4 were launched with several hardware and health-tracking upgrades. Both models use Apple’s new S11 chip and feature an updated Health Sensing System.
The watches can measure heart rate more frequently, provide more detailed heart-rate variability tracking and offer a new readiness score based on factors including activity, training load, vital signs and sleep.
The Apple Watch Series 12 is available in 42mm and 46mm sizes. It offers up to 24 hours of everyday battery life, while Apple says outdoor workout battery life can reach up to 10 hours.
The Apple Watch Ultra 4 is designed for users seeking longer battery life and greater endurance. Apple says it can provide up to 50 hours of everyday use and up to 84 hours in Low Power Mode.
Why the update matters for new buyers
The unexpected restart problem emerged soon after the new watches reached customers, making the software fix particularly relevant for early buyers.
A restart during normal use can be inconvenient, but the consequences could be more noticeable during workouts, when the device may be recording activity and health-related data. Users who have experienced repeated restarts can install watchOS 27.0.1 to address the issue.
Apple has not indicated that the update changes the hardware specifications or adds major new features. Its primary purpose is to resolve the restart bug reported by users of the Series 12 and Ultra 4.
Apple Watch software update arrives soon after launch
The release of watchOS 27.0.1 highlights the importance of early software updates for newly launched hardware. Apple had released watchOS 27 shortly before the new watches became available, but reports of random restarts emerged soon afterwards.
The company has now responded with a targeted update for the affected models. For Series 12 and Ultra 4 owners, installing the latest software should help address the reboot issue while keeping the watches on the latest available version of watchOS.