XADM: Unable to Upgrade Exchange Server 5.5 to Exchange 2000 When the "forestprep" Switch Is Used to Create New Organization

If you attempt to install the first Exchange 2000 server in a Microsoft Windows 2000 forest by upgrading an existing Exchange Server 5.5 computer, the following error message may be displayed when you click Upgrade in the component selection menu of Exchange 2000 Setup:

This issue can occur if you run the Setup /forestprep command and then click Create a new Exchange Organization to create a new Exchange organization instead of joining an existing Exchange Server 5.5 organization before you attempt to install Exchange 2000 on a server. If you run the Setup /forestprep command again after you attempt to install Exchange 2000, Setup no longer displays the Installation Type option during the forestprep phase. To upgrade an Exchange Server 5.5 computer, you must click Join or upgrade an existing 5.5 Organization when you are in the Installation Type section of the installation wizard.

To resolve this issue if there are no other Exchange 2000 servers in the forest, you need to use the Active Directory Service Interfaces (ADSI) Edit snap-in.

WARNING: If you use the ADSI Edit snap-in, the LDP utility, or any other LDAP version 3 client, and you incorrectly modify the attributes of Active Directory objects, you can cause serious problems. These problems may require you to reinstall Microsoft Windows 2000 Server, Microsoft Exchange 2000 Server, or both. Microsoft cannot guarantee that problems that occur if you incorrectly modify Active Directory object attributes can be solved. Modify these attributes at your own risk. It is recommended that you perform a System State backup of Active Directory before you make any modifications with these tools.

To resolve this issue if there are no other Exchange 2000 servers in the forest:

1. Start the ADSI Edit snap-in, which is one of the Windows 2000 Support Tools on the Windows 2000 CD. Click to expand the Configuration naming context. Expand the Configuration folder, expand the Services folder, expand the Microsoft Exchange folder, and then expand the Active Directory Connections folder. Make sure that no Connection Agreements that start with "Config_CA" are displayed. If a Connection Agreement that starts with "Config_CA" is displayed, right-click that Connection Agreement, and then click Delete.
2. Under the Microsoft Exchange container, a container with the name of the organization should be displayed. Click that container, and then click Delete. The ADSI Edit snap-in may stop responding (hang) for up to 30 seconds; this is normal. After the ADSI Edit snap-in completes the operation, the container is no longer displayed.
3. Right-click the Microsoft Exchange container, and then click Properties. On the Attributes tab, next to Select a property to view, click the heuristics attribute. After you click this attribute, click Clear, and then click Apply. You can also click Clear, delete the edit attribute, and then click set. In either case, if the value shows Not Set, the value has been cleared. Click OK.
4. Either allow replication to propagate the deletions to the other domain controllers or force replication by using the Active Directory Sites and Services tool.
5. Run Forestprep and Domainprep. Be sure to join the existing Exchange Server 5.5 organization during Forestprep. You need to install the Active Directory Connector service on a computer in the root domain before you run Forestprep and join an existing Exchange Server 5.5 site.