Marvin

Thanks a lot guys...finally it works now. I appreciate your help! @MartinK @avielc

At last someone came up with helpful information - thanks a lot @avielc I will definitely try your suggested solution and will give you a feedback. Last but not least I have to mention, that I haven't got any duplicates. I only have one (with FQDN) or the other (without FQDN), but never the same client.

For some reason we have clients with FQDN (workstation.mydomain.com) and some without FQDN (computer name or workstation.local) listed in Remote Administrator. Now the funny thing is, that the clients with full qualified domain name are shown in the AD OU as they suppose to, but clients without FQDN are always showing up in the Lost & Found container. So, if you move the clients without FQDN into the correct AD OU they will remain there for a couple of days before they automatically are moved back to Lost & Found again. What can I or do I have to do, so that all Clients are shown with their FQDN and furthermore are not moved into the Lost & Found where they don't belong?