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Article ID: 927374 - Last Review: October 8, 2011 - Revision: 3.0


The Microsoft Compression Client Pack 1.0 for Microsoft Windows XP and Microsoft Windows Server 2003 contains the Msdelta.dll file. The Msdelta.dll file is a library that is part of the Windows Vista operating system. The Msdelta.dll file exports functionality to create and apply binary deltas. These deltas are used to efficiently download updates for Windows Vista. This advanced compression technology is also suitable for many other differential compression scenarios.


MSDelta is the next generation of the PatchAPI compression technology that was included in earlier version of the Windows operating system. MSDelta typically produces smaller deltas than PatchAPI.

In order to obtain the Microsoft Compression Client Pack 1.0 for Windows XP and Windows Server 2003, contact Microsoft Product Support services. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site: (
Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.


For more information about the Delta Compression Application Programming Interfaces, visit the following Microsoft Developer Network (MSDN) Web site: (

  • Microsoft Windows XP Professional x64 Edition
  • Microsoft Windows Server 2003, Enterprise x64 Edition
  • Microsoft Windows Server 2003, Web Edition
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