Help and Support

Err Msg: Uninstall Is Unable to Write to the MBR

Article ID:139107
Last Review:November 15, 2006
Revision:1.1
This article was previously published under Q139107
On This Page

SYMPTOMS

When you try to use the Uninstall option in the Add/Remove Programs tool, you may receive the following error message when your computer restarts:
Uninstall is unable to write to the MBR
When this occurs, the Uninstall procedure cannot be completed, and you may not be able to start the computer from the hard disk.

Back to the top

CAUSE

This problem can occur when any of the following conditions exists:
The hard disk's Master Boot Record (MBR) is damaged.
A software or hardware-level virus scanning program is protecting the MBR.
You are using third-party disk partitioning software.
You computer has been infected with a boot-sector virus.

Back to the top

RESOLUTION

Use the information in the appropriate section below to try to resolve the problem. If you cannot start your computer from the hard disk, you can start it using your Windows 95 Startup disk.

Back to the top

MBR Protected by Virus Scanning Software

If you suspect that a virus scanning program is preventing Uninstall from writing to the MBR, disable the virus scanning program by editing the Config.sys or Autoexec.bat file to temporarily disable the program. Place the word Rem at the beginning of the line or lines used to load the virus scanningprogram. After you make this change, restart the computer.

For information about the virus scanning program, consult the program's documentation or manufacturer.

Back to the top

MBR Protected by Hardware-Level Virus Scanning Program

To disable hardware-level virus detection, run your computer's CMOS configuration utility and disable the virus detection.

For information about your computer's CMOS configuration utility, please consult the computer's documentation or manufacturer.

Back to the top

Third-Party Partitioning Software

If third-party partitioning software is preventing Uninstall from writing to the MBR, refer to the software's documentation for information about restoring the previous MBR or modifying the current MBR.

Back to the top

Boot-Sector Virus

If you suspect that your computer has been infected with a boot-sector virus, use an anti-virus program to detect and remove the virus.

For additional information about viruses, please see the following article in the Microsoft Knowledge Base:
82923 (http://support.microsoft.com/kb/82923/EN-US/) Methods to Detect a Boot-Sector Virus
After you resolve the problem that is preventing Uninstall from writing to the MBR, start your computer with your Windows 95 Startup disk, and then run Uninstall by typing the following command at the command prompt
<disk>:\uninstal <W95undo.dat_location>
where <disk> is the drive containing the Startup disk and <W95undo.dat_location> is the full path to the W95undo.dat file.

Back to the top


APPLIES TO
Microsoft Windows 95

Back to the top

Keywords: 
KB139107

Back to the top

Article Translations

 

Other Support Options

  • Need More Help?
    Contact a Support professional by Email, Online or Phone.
  • Customer Service
    For non-technical assistance with product purchases, subscriptions, online services, events, training courses, corporate sales, piracy issues, and more.
  • Newsgroups
    Pose a question to other users. Discussion groups and Forums about specific Microsoft products, technologies, and services.