This article was previously published under Q127911
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When you attempt to establish trusts among a number of domains usingUser Manager for Domains, the following error message appears:
Cannot create this file when this file already exists
This problem occurs when you attempt establish a trust with a domain thathas the same domain security identification (SID) information as anotherdomain that is already trusted, or has the same local Domain SID. Thisproblem occurs when you:
Rename a domain and the trust to the previous name is still in a trust relationship.
Split a single domain into two domains by simply renaming the domain on some backup domain controller (BDC) and promoting it to a primary domain controller (PDC). In this case both domains have the same Domain SID.
Create two domains through an automated process. For example, you install Windows NT once on a PDC and then performing a disk-to-disk copy to another identical computer, and then change the domain name.
To work around this problem:
If a domain is renamed and previous trust relationships still exist, break all trusts established by the previous domain, and re-create the trusts for the new domain.
Reinstall all domain controllers in one of the domains (consider using a smaller domain). After you re-install the domain controllers, change the security on all objects which give permissions to objects in that domain.
Microsoft has confirmed this to be a problem in Windows NT version 3.5.We are researching this problem and will post new information here inthe Microsoft Knowledge Base as it becomes available.
A domain SID is generated during installation when you decide if you wantthe newly installed computer to be the PDC of a new domain. If there isno domain reachable on the network with that domain name, a new SID isgenerated. If you decide you want the computer to be a BDC, it browsesthe network for a PDC of a domain with that name and use that same domainSID. Once a SID is generated for a domain it does not change. This meansthat if you change a domain's name, it retains the same domain SID.