Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool queries the Win32_Directory Microsoft Windows® Management Instrumentation (WMI) class to determine the value of the Compressed key for the Simple Mail Transfer Protocol (SMTP) BadMail folder. If the Exchange Server Analyzer finds the value for Compressed set to True, a warning is displayed.

When messages arrive at the Exchange computer through the SMTP service, the data is written to the hard disk as an .eml file. By default, these files are stored in the <drive>:\Program Files\Exchsrvr\Mailroot folder on the same partition that Exchange is installed on. If the folder where the SMTP badmail data is stored has file compression turned on, Exchange performance may be severely degraded. Therefore, compression in the folder where the SMTP BadMail data is stored is not supported.

If you receive this warning, you must turn off compression on the folder where the SMTP badmail data is stored, or you must move the SMTP badmail data to a folder that is not compressed.

Microsoft does not support the storage of Exchange data files on a compressed volume. When you store your Exchange data files on a compressed volume, the additional overhead significantly impacts the performance of Exchange. The Exchange data files include all the following files:

To turn off file compression on a given folder

  1. Right-click the folder where you want to turn off file compression, and then click Properties.

  2. On the General tab, click Advanced.

  3. In the Advanced Attributes dialog box, clear the Compress contents to save disk space check box, and then click OK.

To move the BadMail folder on Exchange 2000 Server or Exchange Server 2003

  1. Open Exchange System Manager.

  2. Click Administrative Groups, expand your administrative group, expand Servers, expand your server, expand Protocols, and then expand SMTP.

  3. Right-click your SMTP virtual server, and then click Stop.

  4. Right-click your SMTP virtual server, and then click Properties.

  5. On the Messages tab, next to the BadMail directory box, click Browse, and then type the path of the new location of the Queue folder.

  6. Click OK.

  7. Right-click your SMTP virtual server, and then click Start.

For more information about moving the Mailroot folder, see the Microsoft Knowledge Base article 822933, "How to change the Exchange 2003 SMTP Mailroot folder location" (