Face unlock for Google's Pixel 4 series of phones just keeps breaking. Some claim the Android 11 upgrade is to blame while others point fingers at more recent monthly updates. A reboot can temporarily fix the issue for some, while others are experiencing the problem in tandem with symptoms associated with the seemingly still-unfixed device sensor issue.
Those affected get a "clean the top of your screen, including the black bar" message when trying to unlock their phones using face unlock. In some cases, face unlock might work some small percentage of the time, but for most, the feature is fully broken. But while the precise issue is fairly consistent, the lead-up to those symptoms varies.
The error message for those affected.
Some folks were only affected after the Android 11 update, others have had the issues for a longer period. In some cases, rebooting can resolve things temporarily — on the scale of hours to days — but the problem seems to universally return. The level of detail in reports varies, but for some of those affected, attempting to re-enroll a face also fails. But whether the issue is intermittent or continuous, the ultimate effect remains the same: Face unlock doesn't work. And as the only biometric system available on the Pixel 4 and 4 XL, which didn't have a fingerprint sensor, that's quite an inconvenience.
This isn't the first time we've reported on a related problem. Back in January, a "hardware not available" error affected face unlock on the Pixel 4 for many device owners, and Android 11 Developer Preview 3 could break face unlock if you rolled back to stable Android 10 after installing it.
Google claims that this specific "black bar" issue was fixed in a related thread on the issue tracker, with timing that would otherwise correspond to the November update, but reports continue. The only potentially related fix included in the functional patch notes for the November update is a "fix for dark screen during phone calls" related to device sensor performance on the Pixel 4 series. As touched on previously, some have speculated that these issues are connected and symptoms of the larger and well-known device sensor problem that Google's phones seem to be intermittently affected by. Some of those suffering the issue have further tested device sensors and confirmed that the front-facing proximity sensor and ambient light sensor no longer report data while the issue is happening, indicating that the problems are at least related, if not directly causal.
We have reached out to Google for more information regarding this issue and the below reports, but the company has not responded to our inquiries. If and when we hear any more, we'll be sure to update our coverage.
- Google Issue Tracker; Google Product Forums: (1),
- (6); Reddit: (1),
- (5); XDA Forums: (1),