Windows 95/98

Windows Support Menu


Windows 9X Setup

Windows 98 Uninstall

Windows 98 allows the ability to uninstall itself and return to the Windows 95 configuration at the time you ran Windows 98 setup. This gives users the added securities necessary should they not like or have difficulty with programs while running Windows 98.

Note: Uninstalling Windows 98 returns the operating system to its original configuration. This includes the registry. Any programs installed after Windows 98 was installed will need to be reinstalled after uninstalling Windows 98.

Requirements for Uninstall

The number one requirement for uninstalling to Windows 95 is the user must choose to Save System Files during setup. Without making that choice, there is no uninstalling capability. There are two files saved in the root directory of the boot drive that are used for uninstalling Windows 98; Winundo.dat and Winundo.ini


This file contains all the files necessary to restore the operating system to the original environment when a user selects to save Windows 95 system files. It is used to recreate the Win95 environment originally installed on the computer before Windows 98 was installed. They are Windows 95 specific and are replaced during setup. The files are compressed and placed into one file similar to the way a shareware compression utility compresses an entire folder into one file.
In Windows 95, this file is called W95undo.dat.


This file identifies the files that are placed into the Winundo.dat file. As the file extension suggests, it is an INI file that can be opened for perusing.
In Windows 95, this file is called W95undo.ini

Caution: If a user converts their drive to the FAT32 file system, or compresses a drive with DriveSpace Uninstall will no longer be an option. FAT32 and DriveSpace remove the Winundo.dat and Winundo.ini files from that drive.

Add/ Remove Programs

When you want to uninstall Windows 98 back to Windows 95 or Windows 95 OSR2, click Uninstall Windows 98.

"Delete Windows 98 uninstall information" means to remove the backup information files (Winundo.dat and Winundo.ini), freeing up the 35-75MB of space, but preventing you from returning to Windows 95 or Windows 3.x.

If you manually delete the Winundo files, the Add / Remove Properties sheet will still display "Remove Windows 95 System Files (Uninstall Info)." However, an error message will appear when you click from Add/Remove Programs.