Microsoft KB Archive/313859

= You receive the &quot;Setup cannot uninstall Windows XP because the necessary registration information is missing&quot; error message when you try to uninstall Windows XP =

Article ID: 313859

Article Last Modified on 10/7/2004

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APPLIES TO


 * Microsoft Windows XP Professional
 * Microsoft Windows XP Home Edition

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This article was previously published under Q313859



SYMPTOMS
When you try to uninstall Windows XP by using the c:\windows\system32\osuninst.exe command, you may receive the following error message:

Setup can not uninstall Windows XP because the necessary registration information is missing.



CAUSE
This problem can occur for either of the following reasons.  The Undo folder is not present. The Win9xundodirpath and Win9xundointegrityinfo registry values are not present in the following registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup





RESOLUTION
To resolve this problem:
 * 1) Verify that the Undo folder is present. The Undo folder has the System and Hidden attributes. To view the Undo folder in the Recovery Console, use the &quot;attrib -sh c:\undo&quot; (without the quotation marks) command. By default, the UNDO folder is in the root folder of drive C.
 * 2) Replace the damaged registry with a functional copy of the registry.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.



MORE INFORMATION
307654 HOW TO: Install and Use the Recovery Console in Windows XP

229716 Description of the Windows 2000 Recovery Console

307545 How to Recover from a Corrupted Registry that Prevents Windows XP

303661 Uninstall Windows XP and Revert to a Previous Operating System

Keywords: kberrmsg kbenv kbsetup kbprb KB313859

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