GUID and ProgID Information

Microsoft® XML Core Services (MSXML) 5.0 for Microsoft Office, formerly known as the Microsoft XML Parser, is installed on your computer in side-by-side mode. This means that installing MSXML 5.0 does not replace any previously installed version of the MSXML parser on your computer. This is done to protect the quality of applications that are currently using msxml.dll, msxml2.dll, msxml3.dll or msxml4.dll. Side-by-side mode also allows you to decide which version of the parser to use in your code.

Note   Version-independent GUIDs and ProgIDs are no longer supported in MSXML.

After you install MSXML 5.0, applications that use version-independent ProgIDs continue to run using the latest version of MSXML prior to version 5.0. To use version 5.0, applications must be written to use the appropriate version-dependent class IDs (CLSIDs) and ProgIDs that reference Msxml5.dll.

This ensures stability in your applications. It also enables customers to implement new and improved versioning solutions by using the side-by-side installation technology provided with Windows XP.

• Why Version-Independent GUIDs and ProgIDs Were Removed
• Workarounds to Version Independence
• Assessing the Impact to Your Environment
• MSXML 5.0 GUIDs and ProgIDs