How can I allow a second user account to unlock my device after a reboot?

Question

I recently damaged the screen on my phone and am sending it in for repair. The repair shop I am using wants to be able to access certain features of the device, like the camera, Wi-Fi, etc, in order to test that they still work properly after the repair is complete. I'd like to give them this option without granting them full access to all the data on my phone, and without having to perform a factory reset, so I created a new user account for the repair shop to use.

Unfortunately, while performing the repair the repair shop will need to power the phone down, and here's where I run into a problem. After rebooting my phone, the lock screen for my main user account appears showing the message "Unlock for all features and data.", and doesn't allow switching to the repair shop's account until after the device is unlocked. You can see the repair shop's user account in the settings pulldown menu, but it is greyed out and tapping it does nothing. This defeats the purpose of having a separate account, as it seems my main account's password is required in order to access the repair shop's account.

I am using a Google Pixel, and disk encryption is enabled. (As it is by default.) Note that the Pixel uses file-based encryption, so in theory it should be possible for different users to use different decryption keys for their files. (Though I have no idea if that's possible in practice, which is why I'm asking this question.)

Is there a way to allow other user accounts to access my device after a reboot?

Answer 1

So I had the same problem with an employee to whom I had given a phone. She kept forgetting to charge the phone, so when it rebooted after charging she had to hand me the phone so I could type in the password and then switch to her secondary account. Tired of this, I read some articles about multiple users. I couldn't find the right answers (or didn't understand them) but here is what I did.

1. I switched to her user account and protected her user screen with a swipe.
2. Rebooted
3. In my admin account, I erased/disabled my screen lock by erasing my admin password.
4. Rebooted
5. In my admin account, I enabled the screen lock again by using a password. The phone then prompted me to accept added security by needing a password before startup. This time I chose NO. Then I re-added my old password.
6. Now after reboot, my employee can swipe the screen down and select the second user herself without having to input the admin password. And if she tries to switch to my admin account, the phone asks for my password.

I really don't know how vulnerable the phone has become after declining the added security, but now I can get back to work faster and have one less thing to worry.

I hope someone still finds this helpful.