Domain\Username must be added to a local LANDESK security group on the core before logon is permitted' message appears on all users
This is cosmetic error that leads admins to believe that there is an issue with a users group membership. Users are still able to log in, but this message continues to appear even when group membership is valid.
The 'Username' column in the database has the FQDN (instead of the short name) for the group name. If you look at the screenshot above, you will notice that the group membership section has the cores FQDN instead of the short name.
Solution / Workaround:
Create a backup of the database, modify the following script to match your environment, and run the script on your database:
update consoleuser set username ='Corename\LANDesk Administrators' where username='Corename.domain.NET\LANDesk Administrators'
The same change may need to be made on other groups in the consoleuser table that have a FQDN configured as well.
Relaunch the console and verify that the issue is resolved.