Error Message: The File C:\W95undo.dat Cannot Be Read

Last reviewed: October 10, 1995
Article ID: Q137940
The information in this article applies to:
  • Microsoft Windows 95

SYMPTOMS

When you try to uninstall Windows 95, you may receive one of the following error messages:

  • The file C:\W95undo.dat cannot be read. Error Code -6: Unexpected end of file.
  • The file C:\W95undo.dat is invalid or incomplete. Error code -4: Invalid signature.

CAUSE

The W95undo.dat file is missing or damaged. You cannot uninstall Windows 95 automatically if this file is missing or damaged.

RESOLUTION

To restore your previous version of Windows, follow these steps:

  1. Restart your computer using an MS-DOS boot disk that contains the Sys.com file.

  2. At the MS-DOS prompt, type the following line and then press ENTER:

          a:sys c:
    

    NOTE: If drive C is compressed, substitute the letter of the host drive (such as H) for drive C.

  3. Delete the Windows folder.

    NOTE: The Windows folder may contain files use by other Windows-based programs. If you delete the Windows folder, you must reinstall all your Windows-based programs.

  4. Reinstall Windows 3.x.

MORE INFORMATION

When you install Windows 95, you are prompted to back up the current system files. If you choose to do so, the Windows folder and all its contents are backed up to a hidden, compressed file called W95undo.dat. This file is used to restore the previous version of Windows.


KBCategory: kbsetup kberrmsg
KBSubcategory: win95
Additional reference words: 95


THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Last reviewed: October 10, 1995
© 1998 Microsoft Corporation. All rights reserved. Terms of Use.