A. Microsoft has removed the M drive by default in Exchange 2003 because of problems related to backup and antivirus software running against the M drive. However, you can still use the \\.\BackOfficeStorage\ namespace to access the Exchange information through file APIs.
If you require the M drive (e.g., you have programs that use the M drive to map the Installable File System, you use Microsoft FrontPage Extensions and the Microsoft Web Storage System--WSS), you can enable the drive by performing the following steps (but do so at your own risk):
- Log on to the Exchange server as an administrator.
- Start a registry editor (e.g., regedit.exe).
- Navigate to the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EXIFS\Parameters registry subkey.
- From the Edit menu, select New, String Value.
- Enter the name DriveLetter, then press Enter.
- Double-click the new value, set it to M, then click OK.
- Close the registry editor.
- Restart the Exchange server (or restart the Information Store service) for the changes to take effect.