Active Directory server is running Windows 2000 Server and has the /3GB switch set

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at]  

Topic Last Modified: 2005-11-17

The Microsoft® Exchange Server Analyzer Tool queries the Win32_OperatingSystem Microsoft Windows® Management Instrumentation (WMI) class to determine the amount of virtual address space allocated to user mode processes (MaxProcessMemorySize) and the version of Windows (OSProductSuite) that is running on the Active Directory® directory service server. The following table describes the classes and keys being evaluated by the Exchange Server Analyzer.

If the Exchange Server Analyzer determines that the value for the MaxProcessMemorySize is 3104640, and that the value for OSProductSuite resolves to Windows 2000 Server, an error is displayed.

This error indicates that the /3GB startup switch is set in the Boot.ini file on a directory server running Microsoft Windows 2000 Server. This switch is not supported on Windows 2000 Server, and should be used only on computers with 1 GB or more of memory that are running any of the following operating systems:

  • Microsoft Windows Server™ 2003 Standard Edition

  • Microsoft Windows Server 2003 Enterprise Edition

  • Microsoft Windows Server 2003 Datacenter Edition

  • Microsoft Windows 2000 Advanced Server

  • Microsoft Windows 2000 Datacenter Server

To remove the /3GB switch from the Boot.ini file

  1. In Windows Explorer, navigate to the system partition.

  2. If you are unable to see the Boot.ini file, it could be because the Folder Options are set to Hide protected operating system files. If this is the case, in Explorer, click Tools, Folder Options, and then click the View tab. Clear the Hide protected operating system files (Recommended) check box. When prompted with the warning box, click Yes.

  3. When the Boot.ini file is visible in Explorer, right-click the file, click Open With, and choose Notepad to open the file.

  4. In the [Operating Systems] section, delete the following switches from all startup lines: /3GB /USERVA=3030

  5. Save the changes and close Notepad.

  6. Restart the directory server for the change to take effect.

For more information about using the /3GB startup switch, see the following Microsoft Knowledge Base articles: