If you have direct SQL access you can copy and paste in to SQLyog and execute it. If your hosted via hostedrmm.com then create a new automate script and call it LUM purge. The first function to add should be the “ SQL Execute “ function. Copy and paste the full query below in to that function and save script. Execute the script on any one agent and only once. This should clear the data from the displays. Any time you get data in there from retired systems just execute the script again. You can execute the script as often as you like. It will not harm any data where agents still exist and are active.
DELETE FROM plugin_p4l_lum_packages WHERE ComputerID NOT IN (SELECT ComputerID FROM computers); DELETE FROM plugin_p4l_lum_status WHERE ComputerID NOT IN (SELECT ComputerID FROM computers);