Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool reads the following registry entry to determine the files and folders that have been excluded from backups using Backup:


The Exchange Server Analyzer specifically looks for a string value called Exchange IFS.

The Exchange Server Analyzer also reads the following registry entry to obtain the drive letter that represents the Exchange Installable File System (IFS) drive:


In Exchange 2000 Server, the default drive letter is M. The IFS drive is turned off by default in Exchange Server 2003.

If the Exchange Server Analyzer finds that the FilesNotToBackup key does not contain a string value called Exchange IFS, or if it does contain Exchange IFS, but the value data for Exchange IFS does not equal M:\* /s (where M is the drive letter representing IFS), a warning is displayed.

By default, when the IFS drive letter mapping is enabled, Exchange IFS is added to the FilesNotToBackup registry key. The M:\ drive is a logical view of the Exchange store, and not a true drive, and backing it up can cause significant problems such as lost attachments. In addition, the backup software may not truncate the log files as appropriate, which can result in the server running out of disk space unexpectedly.

If you are not using Backup, you can safely ignore this warning. If you are using Backup, it is recommended that you exclude the IFS drive from all backup jobs. If you back up the IFS drive with Backup or any other backup program, you might corrupt your information store databases, lose data, and not be able to restore data from a backup of the IFS drive.

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

To correct this warning

  1. Open a registry editor, such as Regedit.exe or Regedt32.exe.

  2. Navigate to: HKLM\System\CurrentControlSet\Control\BackupRestore\FilesNotToBackup

  3. Right-click FilesNotToBackup and click New | Multi-string value. Type Exchange IFS for the name and press Enter.

  4. In the right pane, double-click Exchange IFS and enter a Value Data of M:\* /s. Be sure to use the correct drive letter in case your system does not use the default drive letter M.

  5. Close the registry editor.

For more information about the Microsoft Windows® registry, see the Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows Registry" (

For more information about backing up and restoring Exchange, see the Exchange Server 2003 Disaster Recovery Operations Guide ( For additional information, see the following Knowledge Base articles:

For more information about problems that may occur if you scan the IFS drive with antivirus software, see the following Knowledge Base articles: