I have made the transition to using a password manager so my multiple accounts are protected with more complex passwords. I should have anticipated a problem using my chromebook, but I did not. The default way you activate your chromebook is with your Google password. LastPass automatically will enter your complex passwords for most services, but not as a way to open your chromebook. The solution is to switch your chromebook activation from your Google password to a pin. This is much easier to do before you create a complex password for Google, but you should be able to see your new Google password using a different device, take the time to enter this complex password a few times on the Chromebook to make the switch to a pin, and then you should be fine. I am not certain what you would do if your chromebook is your only device.