Issue: On Mac OS 10.13.6, when a domain user logs in to the domain joined Mac Client in the offline mode and tries to unlock any preference pane using the lock icon in the lower-left corner, the preference does not get unlocked to change settings. This issue occurs when the user is not granted the administrator privileges.
Workaround: Perform the following steps to grant the administrator privileges to a specific user:
Log in as a domain user and create a mobile account.
Click System Preferences > Users & Groups.
Select the preferred mobile account.
Select Allow user to administer this computer.
Restart the operating system.