For some, the snazzy new face unlock system on Google's latest Pixel 4 is a whole lot less convenient than it should be. Reports over the last couple of months indicate that the face unlock process is simply failing for a handful of Pixel 4 and 4 XLs, even after re-enrolling their faces or resetting the phone. Thankfully, the issue doesn't sound too widespread.
The problem first popped up starting around November, escalating in frequency over more recent months. For many, the issue first appeared immediately after receiving one of Google's (recently delayed) monthly security updates, though it's also occurring without any apparent triggering action for others. Although there are reports of the issue at venues like the Pixel support forums, Reddit, and the XDA Forums, with some threads around 20-40 comments deep, the problem doesn't appear to be particularly widespread.
For those affected, two subtly different error messages are appearing when they attempt to use face unlock, which could indicate two different but potentially similar problems: "Can't verify face. Hardware not available" and "Can't verify face. Try again." For many that get these error messages, deleting and re-adding face data does not fix the issue.
The two error messages associated with the problem(s) that some are seeing.
For a handful of those affected, the issue was preceded by a notification that they needed to re-enroll in face unlock, but following that instruction to remove and re-add their face data fails to fix the problem. Some are also unable to even delete the phone's stored face data in Settings.
Restarting the phone in safe mode reportedly doesn't help. Although some reports indicate that the issue was resolved after a factory reset, others are running into the same problem even after a wipe.
We've reached out to Google about these reports, and it's looking into them. In the meantime, those affected can attempt a factory reset as a last-ditch solution, though it doesn't always fix the issue. Sadly, the phone doesn't give its owners a backup system like a fingerprint sensor to fall back on, so those suffering the problem are stuck using a PIN, pattern, or password for security in the meantime.