Troubleshooting unknown objects coming back

The purpose of this TID is to give you some guidelines on how to troubleshoot an unknown object that comes back after it has been deleted.
It is also possible that you notice this problem after deleting one particular object and see it's name come back a while after the deletion. The object may appear back right after it has been deleted or in some cases it may come back only after a few hours it has been deleted.

The first thing you need to try to determine is what kind of object this object was before it was deleted. There are normally two categories of objects that could present this behavior and there are different troubleshooting paths depending on which kind it is:

1. NCP Server objects and the containers where they used to reside.
2. All other kind of objects that normally have a reference to a different objects, like for example users, groups, printers, etc.

In the first case you may notice first a former Organization or Organizational Unit showing up as an Unknown Object from your administration utility. Checking for object underneath you find the existence of the Server objects. Most likely these servers are no longer being used and are not part of the tree anymore (given the fact that you were trying to delete the NCP server object). There are two well known conditions that will cause a Server object to come back:

1. This was a Netware server and DS has been uninstalled from it, but the server is still powered on. The server has IPX bound to it and SAP is still broadcasting its existence. You can check with the command "display servers servername" in the command line of a server that has the unknown object to see if this server is receiving that broadcast. If that is the case, then locate the original server and make sure it remains powered off. In this case the backlinker process is the one that causes the object to come back. It may take a few hours until the object reappears.
   
2. Though the server has been taken out of the tree and is no longer available, some partitions still have this server listed in their replica ring. You can use iMonitor's tree wide report to detect if there are some partitions that have had synchronization problems for a long period of time to determine the possible suspects. You can then use dsrepair -A|Advanced options|Replica and partition operations|choose the partition|Remove from replica ring to remove the problem server from the replica ring. In this case it's the sync process that causes the object to come back so the object normally reappears almost immediately.

If the object coming back is not an NCP Server object (or not only a server object), the reason for it might be that there is a reference to the object that is not being correctly processed. You can use dsrepair -at to check if the problem is caused by a duplicate Creation Timestamp or check to see if there is a condition of continuous sync affecting the partition where the problem happens. For more information on how to troubleshoot this particular kind of problem, check out KB 10092390: Object comes back as Unknown after it has been moved or deleted.