While updates are often beneficial and offer bug fixes, the recent Chrome OS 91.0.4472.165 has caused users to be locked out of their Chromebooks.
Google confirmed the faulty Chrome OS update
Google has also confirmed the unfortunate event and pulled the update. For those who are affected, Google offered three workarounds, but these methods will clear your local data.
Fix will come soon
According to Google support, you can powerwash your Chromebook, rollback to the previous Chrome OS via USB, or remove your account before adding said account back to your device. But if you’re willing to wait, Google has a fix that’s supposed to come today.
A new Chrome OS 91 update will be made available today; with this update, users can update their Chromebooks manually by logging into Guest Mode. Another alternative is to leave your Chromebook on the login screen — this will allow the update to be downloaded via auto-update.