This article was previously published under Q317393
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If you rebuild a Microsoft Windows 2000 Server-based computer on which Exchange 2000 Server was originally installed, and that server is still listed in Active Directory as an Exchange 2000 server, you should be prompted with the following message when you run the Exchange 2000 Setup program:
There is an existing server object in the Active Directory, please run setup in Disaster Recovery mode.
If you restore the system state to that Exchange 2000 server, and then run Exchange 2000 Setup, you may not be prompted with that message.
This problem can occur if the system state is restored. Exchange 2000 Setup reads the restored registry and incorrectly determines that Exchange 2000 is correctly installed on the local computer.
To resolve this problem, obtain the latest service pack for Microsoft Exchange 2000 Server. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
301378 XGEN: How to Obtain the Latest Exchange 2000 Server Service Pack
To work around this problem, when you restore an Exchange 2000 server after you restore the system state, make sure that you run Setup with the /disasterrecovery switch, instead of running Setup without the switch and selecting the Reinstall option.
If you run Setup with the /disasterrecovery switch, Setup prompts you to restore the databases from a backup at the end of the installation, before the services are started. If you run Setup without the switch and select the Reinstall option, Setup does not prompt you to restore the databases before starting the services.
IMPORTANT: You may experience data loss if you do not use the /disasterrecovery switch when you run the Setup. If you select the Reinstall option, the services are started when the installation is complete. At that point, new, blank databases are up and running. If other servers in the Exchange organization have been queuing up mail for the server that you are restoring, the mail is delivered to the new databases. To prevent mail loss, you must pull the mail out of these new databases before you restore the old databases. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
174197 XADM: Microsoft Exchange Mailbox Merge Program (Exmerge.exe) Information
Microsoft has confirmed that this is a problem in Microsoft Exchange 2000 Server. This problem was first corrected in Microsoft Exchange 2000 Server Service Pack 3.
On the components dialog box in Setup, make sure that Disaster Recovery is displayed under Action for any previously installed components. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
296790 XADM: Setup /disasterrecovery Does Not Detect Previously Installed Components