The next time you grab a spare Android phone or tablet, don’t be surprised to find it locked after being rebooted for security reasons. This week, Google started rolling out a new security feature for Android that will automatically restart devices that have been sitting idle for three days or longer.

Google often improves devices through behind-the-scenes updates to the Google Play services app instead of with a significant over-the-air OS release, and that’s what’s happening right now. We expected this feature to go live later this year as an aspect of Android 16’s Advanced Protection Program, but it’s arriving already.

According to 9to5Google, the latest April Google Play services version 25.14 update changelog notes a new feature where Android devices will “automatically restart if locked for three consecutive days.” This change only applies to phones and tablets (not TVs, etc,) and will only reboot devices, meaning all of your data is safe. This is not a reset but a simple power off/on reboot.

So, why would Google make such an interesting change? It’s actually to improve security on devices that sit idle too long or are otherwise not used regularly. That way, spare devices or an old Android device you repurposed remain safe and secure.

By restarting the device, it enters a Before First Unlock (BFU) state, where biometrics like fingerprint unlock aren’t available yet. Instead, the device is in an encrypted state that’s harder to access and requires a password, pin, or pattern unlock first. After three days of inactivity on a phone or tablet, the device may reboot and return to the BFU state. Then, you’ll simply need to enter your pin or password to start using it again.

For what it’s worth, this is not a new concept. Apple added a similar feature to iOS 18 last year, where an iPhone or iPad would reboot after seven days. However, it later changed that to three days in an update to iOS 18.1 a month later. Additionally, other Android-based operating systems, like GrapheneOS, have a similar function.

In a somewhat similar fashion, Samsung Galaxy devices let you set an automatic reboot after a set number of days, which can improve security and performance. However, this feature isn’t based on activity and will simply reboot a device regardless of its state as soon as it reaches the time and date specified. Google’s new feature is being automatically applied to devices for optimal security.

We’re unsure which Android devices will get this latest security feature or when the Google Play services update will roll out to all users. In the meantime, you can head to Settings > Security & privacy > System & updates > and tap on Google Play system update to manually check.

We don’t know if Google plans to add any settings to let users customize this feature, and it’ll likely happen automatically. Nor do we know if the lock screen will alert users that a reboot has occurred. That said, you’ll typically see an icon in the notification shade after rebooting an Android phone that mentions the device has been restarted and to unlock the device to get app notifications. I imagine Google’s new update will operate in a similar fashion.

Source: 9to5Google via The Verge