XADM: How To Restore a 4.0 Directory To a 5.0 Server (185005)

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.

SUMMARY

In some situations, it may be necessary to restore an older directory created in Exchange Server 4.0 to a computer running Exchange Server 5.0. One solution to this issue is to completely uninstall and then re-install Exchange Server 4.0, and subsequently, upgrade Exchange Server 4.0 to version 5.0. Because this would be quite time consuming, the following method in the More Information section can be used.

MORE INFORMATION

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.

Stop the Exchange Server 5.0 directory service.
Restore the copy of the directory from the Exchange Server 4.0 backup, and choose to erase all existing data.

Open the registry editor and change the following key so that the value is 1 DWORD:

       HKLM/SOFTWARE/MICROSOFT/EXCHANGE/SETUP/Disaster Recovery Status

Run Setup again to upgrade the directory. The directory will be upgraded to version 5.0, and the Disaster Recovery Status Key will be set back to 0.

Uninstallation and re-installation with the setup /r option on Exchange Server 5.0 will also set the Disaster Recovery Status Key to 1, so that an upgrade of the database will be performed in the event that an Exchange Server 4.0 directory is restored to the server. After you perform the restore, a 5.0 upgrade will also need to be performed.