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

Article ID: 313859

Article Last Modified on 10/7/2004

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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.

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

To resolve this problem:

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 "attrib -sh c:\undo" (without the quotation marks) command. By default, the UNDO folder is in the root folder of drive C.
Replace the damaged registry with a functional copy of the registry.

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

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