When the inventory scanner runs, it first looks for a preexisting Device ID. On Windows clients, that value is set in two places, HKLM/Software/Intel/LANDesk/CommonAPI and HKLM/Software/LANDesk/CommonAPI. (The former is the one that matters for ldiscn32.exe, but bad things will happen if they aren't the same.) On OS X clients, it's /Library/Preferences/com.landesk.uuid.plist.

If the UUID doesn't exist, the inventory scanner creates a new random one and submits it to the core with its first inventory scan. This is the first point where problems can occur... if this piece of hardware was already in the inventory database and you've just reimaged it, then there's now a duplicate record.

LANDesk Management Suite is a huge and complex product, and few shops use everything. Its OS Deployment takes care of this problem on the fly, but it can't do that if you're not using it. That's why this screen exists at Configure > Services > Inventory > Devices.

The first three boxes control removal of devices during the nightly database maintenance routine... the last one is the most interesting though, because it looks up the old Device ID and tells the workstation to take it back. Windows only, of course.

Of course, MAC addresses can be somewhat unreliable... maybe you're lucky enough to be working with hardware Asset Tags or serial numbers instead. That takes us to the next button, at Configure > Services > Inventory > Device IDs.

There's two non-self-explanatory bits to twiddle here... first, the Triggers. The most important thing to know here is that when a record is "Logged as a duplicate device ID" it will be deleted during the nightly database maintenance. So, theoretically, the older record of a reimaged machine is supposed to disappear that night. If this worked in practice at some point in the last five years, it's news to me... but I haven't bothered to chase down why since ldms_core gives you duplicate reports.

The second place to change behavior is that Reject Duplicate Identities checkbox, which should tell the inventory service to evaluate what it's getting from the client during transmission and reject the scan if it looks duplicated.

Astute readers will have noticed that there's a conflict here... if the MAC address is the same, the first screen says to restore the old device ID, but the second screen says to reject the scan. As far as I can tell, the first screen wins, so if you want the behavior of the second screen, you should turn off the Devices option.