Setup Setup a Google OAuth2 service Untick the "Require email verification" Go to Site administration / Plugins / Authentication / Manage authentication. Enable the oAuth2 authentication mechanism Editing an existing user Still as an admin, navigate to Site administration -> Users -> Browse Edit an existing user, s1, and set the Gmail account's e-mail address as the user's e-mail address On another browser session/incognito window, log in using the Google login using s1's Google account. Confirm that your name hasn't been changed to your Google account's name Log out and log in again using s1's username and password. Confirm that you can log in. Log out. Back on the admin's browser window, edit s1's profile. Change s1's authentication method to OAuth 2 Save the changes. Log in again as s1 using the Google authentication. Confirm that s1's name has been changed to the Google account's name. Log out. New user creation Log in via OAuth2 again using a different Gmail account which is not yet registered in your Moodle instance. Let's call this user as s2 Confirm that the account was created Confirm that the details of that account were also pulled in Linked login Log in as a user s3 Go to your user preferences and go to Linked logins. Link another, non-existing google account to your account. Confirm that you can link your account successfully. Log out. Log in as s3 using your linked Google account. Confirm that you can log in. Confirm that your details have not been changed. Log out and log in again using s3's username and password. Confirm that you can still log in. Locked profile fields Back on admin's browser, go to Site administration / Plugins / Authentication / OAuth 2 Set the First name's lock value to Locked. Save the changes. Manually edit s2's first and last names. Save the changes. On s2's browser window, log in again as s2 using Google authentication Confirm that s2's first name hasn't been changed, but s2's last name has been synced with the Google account's last name.