Some Apple Watch users who updated to watchOS 11.6.1 alongside iOS 18.6.1 are finding that the Blood Oxygen app will not launch or shows as unavailable. This is despite the update being designed to reintroduce the feature in the United States after it was temporarily disabled due to a patent dispute.
The issue appears to be affecting certain models and configurations, where the watch fails to recognize that Blood Oxygen measurements should be available again. While Apple has not yet acknowledged the problem publicly, a simple workaround shared by Apple-focused content creator Aaron Zollo has helped some users restore the feature.
The Blood Oxygen app is available on Apple Watch Series 6 and later, including Apple Watch SE (2022), Apple Watch Ultra, and Apple Watch Ultra 2. It is not supported on earlier models such as Series 5, Series 4, or the original Apple Watch SE. If you have a compatible model and still cannot use the feature after updating, you may be affected by the bug described below.
How to fix Blood Oxygen not working on watchOS 11.6.1
Zollo’s method uses other health sensors on the Apple Watch to “wake” the Blood Oxygen function:
- Open the Heart Rate app on your Apple Watch.
- Take a manual heart rate reading.
- Open the ECG app.
- Perform a full ECG reading.
After completing these steps, the Blood Oxygen app may reappear as active, allowing you to take measurements normally.
Why this Blood Oxygen fix might work
The exact reason this sequence works is unclear, but it likely forces watchOS to refresh sensor permissions and availability, triggering the Blood Oxygen feature to become accessible again.
More ways to restore Blood Oxygen on Apple Watch
If the workaround does not solve the issue, you can also try:
- Restarting both your Apple Watch and paired iPhone.
- Checking that Blood Oxygen is enabled in the Health app on iPhone.
- Unpairing and re-pairing the Apple Watch.
Blood Oxygen’s return in watchOS 11.6.1
Apple’s reactivation of Blood Oxygen in watchOS 11.6.1 follows a redesign aimed at avoiding infringement of a contested wearable patent. The updated version is intended to offer similar functionality while complying with the legal ruling that previously led to its removal in the U.S.
For users experiencing the bug, trying the Heart Rate + ECG sequence could be a quick and effective fix before seeking further support from Apple.
