Reset the domain computer account for the lost server. To do this:

1. Open Active Directory Users and Computers.
   
   
2. Locate the computer for the lost server.
   
   
3. Right-click the computer name, and then click Reset Account.
   
   

Bring the new server running Microsoft Windows Server 2003 online, and join it to the domain with the same name as the lost server.

Configure all drives with the same logical assignments that were present on the missing server.

Open a Command Prompt window in your Exchange source folder, and run the following command:

	Copy Code
setup /m:recoverserver

Note:
The source folder is the processor type identifier folder (\i386 or \amd64) on your DVD or other source media.

To allow Setup to run again, you must first identify the roles that were recovered. If the setup console from the first attempt is still visible, the recovered roles have "COMPLETED" next to their names. Otherwise, you must go to the registry and open the key:

HKEY_LOCAL_MACHINE\Software\Microsoft\Exchange\v8.0

Several subkeys with the names of server roles (for example, "MailboxRole") are under the v8.0 key. Examine each subkey. If the subkey contains both an UnpackedVersion value and a ConfiguredVersion value, and both values are the same (which will be a string such as "8.0.685.23"), that server role is successfully recovered and installed. Make a note of which roles have been successfully recovered.

Note:
Incorrectly editing the registry can cause serious problems that may require you to reinstall your operating system. Problems resulting from editing the registry incorrectly may not be able to be resolved. Before editing the registry, back up any valuable data.

Back up the data that you intend to modify in both the registry and Active Directory. In the registry, open the key:

HKEY_LOCAL_MACHINE\Software\Microsoft\Exchange\v8.0

Right-click this key, select Export, and then save the file.

Using AdsiEdit (AdsiEdit.msc), find the Exchange server object for the server that you are recovering. For example, the following is a path to a server object:

CN=<name of server>,CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=<name of organization>,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=<name of domain>

Make note of the value of the attribute msExchCurrentServerRoles; it is an integer. The value of this attribute on the server object indicates the roles that were configured on the server object before the failure, and it is derived by adding values as follows:

Change the variables that Setup reads to force it to disregard the roles that were recovered and recover the roles that were not recovered. This requires temporarily altering the information in the registry and Active Directory:

1. Using regedit.exe   For every successfully recovered role, rename its key under HKLM\Software\Microsoft\Exchange\v8.0 by appending a 0 or otherwise changing the name of the key.
   
   
2. Using AdsiEdit.msc   Take the current value of msExchCurrentServerRoles, subtract the value corresponding to the recovered roles, and then modify the attribute to the new value. For example, if you have successfully recovered the Mailbox role on a server with the Hub (value = 32), Mailbox (value = 2), and CAS (value = 4) server roles installed, you have a value of 38. From that value, subtract 2 for the Mailbox role, which leaves a value of 36 for msExchCurrentServerRoles.
   
   

Run Setup /m:RecoverServer as you did before to recover all the remaining unrecovered server roles.

After the recovery is finished, restore the edited values in the registry and Active Directory:

1. Using regedit.exe   Setup will have created new keys corresponding to the previously renamed keys for successfully recovered roles. Delete those keys, and rename every key under HKLM\Software\Microsoft\Exchange\v8.0 back to its original name.
   
   
2. Using AdsiEdit.msc   Modify the value of msExchCurrentServerRoles back to its original setting.