Wednesday, July 27, 2011

ADMT is unable to connect to domain controller. 0x80070005

I am performing cross forest migration from 2 AD forests, multiple domains into a new AD forest. When I added one of the domains within a source forest I received the following error:

ADMT is unable to connect to domain controller
\\domaincontroller.sourcedomain.local, in domain sourcedomain.local. Access is denied.

Morgan Che posted up multiple causes for this error on the following forum thread:

I had a different problem to the ones mentioned on the above forum thread. One of my forests was setup with whats called a single labelled domain name. ADMT was having difficulties communicating with all domains within the single labelled forest.

To resolve this on the ADMT server I needed to add a DWORD registry key "AllowSingleLabelDnsDomain" with a decimal value of 1.

ADMT was then able to communicate with all domains in the forest which had a single labelled root domain.

For more information on this registry key please see:



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  5. Any thoughts on the below issue? I am getting the same error, just a different scenario. What would you do for this?
    I am having difficulty migrating a DMZ domain to an internal domain. I just need to migrate users, groups and passwords. The target domain is (a tree root domain of which is in the Forest with 4 total domains. The source of the migration is in the Forest (also a tree root domain). Both domains in the RootB Forest ( and are in the DMZ. There is a one-way Forest trust (That is Transitive) between and ( is listed as a Domain trusted by this domain (outgoing trusts) in & is listed as a Domain that trust this domain (incoming trusts) in contains the DNS servers for all of the domains (the 4 domains in Forest and 2 domains in the Forest). So I didn't have to do anything with DNS to create a two-way external non-transitive trust between and The trust was established and validated. I built a temporary server named TEMPADMT to run ADMT v3.2 in the (target) that runs SQL Server Express 2008 SP1. ADMT v3.2 installed without any issues. I installed PES on's PDC, generated a key and applied it (that went smooth). My issue is when I open ADMT and go to select the Source and Target domains. The Source ( is not listed, but I am able to type it in and it finds the two domain controllers in the domain. The Target ( is listed and I am able to select it and the domain controller no problem. When I click next I get the following Error: ADMT is unable to connect to domain controller \\ in domain Access is denied. (0x80070005). I tried logging in to the TEMPADMT server with the admin account and running it with those credentials, but I get the same error, this time for - Error: ADMT is unable to connect to domain controller \\ in domain Access is denied (0x80070005). I built a test setup (the best I could - 5 servers (one for each domain) I was not able to build the DMZ in the test lab) to try to duplicate the issue but was unable to replicate the problem... unless I removed the external trust and then I was presented with the same error. I validated the trusts and made sure they were active and running. In order to try this migration I had my security team open Any>Any firewall rules (inbound and outbound) between 1)'s PDC and's PDC 2) and's PDC. Any help is much apprecaited.
