After a full Active Directory forest restore and performing a /DisasterRecovery mode recovery of Exchange 2003, I kept getting running into an error that halted the setup. [18:27:02] Setup encountered an error while checking prerequisites for the component "Microsoft Exchange Messaging and Collaboration Services": 0XC007003A (58): The specified server cannot perform the requested operation. The setup log Exchange Server Setup Progress.log contained a clue. Setup tried to connect to a GC server from the same site that was not restored and didnt attempt a connection any other GC in that site. [18:18:55] Searching for GCs in site "/dc=com/dc=enterprise/cn=Configuration/cn=Sites/cn=Root" [18:18:55] Processing GC "/dc=com/dc=enterprise/dc=dom1/ou=Domain Controllers/cn=dc10" [18:19:31] Could not open LDAP connection to the server dom1.enterprise.com Several lines below this, described what I thought was setup.exe resolving the problem with connection to my /ChooseDC selection with the message: [18:19:31] === IGNORING PREVIOUS ERRORS === HrSetProblemOnInstallAction, while calling ScCheckPrerequisites (f:\titanium\admin\src\udog\bo\comboifaces.cxx:1399) The operation has completed successfully. I mentioned this is a full forest recovery and in the interest of getting operational quickly and per the MS Operations Guide, a single domain controller for each domain was initially restored. The error occurred despite using the /chooseDC Exchange server setup option. Despite several attempts to force setup to another GC in the site, I realized I needed to remove all servers not restored from the site before I could continue. The workaround was effective and I dont seem to have a problem now, I felt it was interesting and worthyof mentuion that the Exchange setup did not attempt to locate a GC it could speak to and that the /ChooseDC option was also not an effective solution.

Interesting note. I have done a test restoretwice in the past and must've got lucky with regards to the GCs it selects. The picking up a server that cannot be reached when there's loads of others available is a common theme with MS products. Take KCC for example. KCC will choose a replication partner for a DC even if the other DC cannot be reached. MS assumes an always on fully meshed network!