New Apple Watch Models Reboot Due to Neural Engine Timeouts

Owners of the new Apple Watch Series 12 and Ultra 4 are reporting that their devices are restarting without warning. These incidents have occurred shortly after the watches went on sale in mid-September, affecting users during various daily activities.

Diagnostic files shared by affected users point to a specific cause: the Apple Neural Engine is timing out. This suggests the processor is hanging for a brief period before the system forces a restart to prevent a complete failure.

Reboots occur during varied activities

The restarts are not limited to a single app or function. Users have seen the Apple logo appear while using Siri, editing watch faces, making calls, or recording workouts. In some cases, the watch restarted while idle, leading to gaps in health data or lost workout sessions.

Logs indicate a processor hang

The strongest evidence comes from 'panic-full' logs, which record low-level system crashes rather than simple app errors. Multiple logs show the same Neural Engine timeout, where the chip hangs for about two seconds. This pattern suggests a common fault in the new S11 chip or its supporting software.

The S11 chip handles more on-device processing than previous generations, supporting features like advanced heart-rate tracking and audio functions. The increased workload may be straining the system, though it is unclear if the issue lies in the hardware, watchOS, or the Neural Engine firmware.

Resets may not resolve the issue

Erasing the watch and resetting it to factory settings has not consistently fixed the problem. One owner reported receiving a replacement device that exhibited the same behavior. This makes it difficult to guarantee that a simple reset or hardware swap will resolve the crash.

Apple has not acknowledged the issue or provided a specific workaround. While some beta testers suggest version 27.2 may reduce crashes, there is no confirmed public fix. Affected users are advised to check for the latest watchOS updates and save diagnostic logs to help Apple Support identify the root cause.