XADM: How To Restore a 4.0 Directory To a 5.0 Server

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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.

1. Stop the Exchange Server 5.0 directory service.
2. Restore the copy of the directory from the Exchange Server 4.0 backup, and choose to erase all existing data.
3. Open the registry editor and change the following key so that the value is 1 DWORD:
   

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

4. 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.