Background

A ADC was previously used in a domain to migrate from Exchange 5.5.  The server was formatted/lost without removal of the ADC, leaving ghosted AD entries in the metabase.

Error message

     One or more Active Directory Connectors have been found. Please remove all Active Directory Connectors before installing Exchange 2007.

Solution

1. ADC was installed and uninstalled from Exchange 2003 media.  \ADC\i386.
2. Replicate all DC connections in Sites and Services.
3. Next, access ADSIEdit - install from \SUPPORT on Server 2003 disk if necessary.
4. Open the Configuration container, the the Configuration folder, CN=Services.
5. Open the Microsoft Exchange folder, and the Active Directory Connections folder.
6. Only the default ADC policy should exist - DELETE any references to Exchange 5.5 in a secondary connector.
7. The image below shows a fully functional configuration, with the EXCH/5.5 connection removed.
8. Replicate all the AD connections via Sites and Services before reattempting installation.