Can't delete removed client computer in Malwarebytes Management Console Posted November 5, 2019 · Edited November 5, 2019 by djacobson A greyed out 'remove client' option means your machines and groups are AD OU imported entries. AD OU is a mirror in MBMC, you cannot perform a deletion from your AD via MBMC. If the machine has already been decommissioned from AD, delete and re-add your whole AD OU group in MBMC to force a re-sync. If the machine has not been decommissioned from AD properly, you can use the cleanup options in the Admin tab -> Database Settings -> Cleanup Settings -> 'Delete Obsolete clients ____', 'when client has not accessed server for ____ days'. Note that the last option will drop a client from the MBMC database table when it has not accessed the server for x amount of days; but if it still exists in AD, anytime your AD OU re-syncs, the machine will be back.