If you have upgraded from another version of Windows and chose to save your previous version of Windows during the upgrade, you will be unable to uninstall back to your previous version of Windows with this update installed.
Disabling the option to uninstall Windows ensures that your system continues to support your large IDE drive.
Important Notes About Upgrading from Windows 98 to Windows 98 Second Edition
When you install this fix on Windows 98 (original edition), the Windows 98 Second Edition version of the fix and a migration DLL are copied to your system as well. If you later upgrade to Windows 98 Second Edition, the Windows 98 Second Edition version of the fix is automatically installed during the upgrade process. This ensures that you do not lose the functionality provided by this fix by upgrading to Windows 98 Second Edition.
For this automatic migration to occur, you must run Windows 98 Second Edition Setup while running Windows 98. If you boot to a command prompt, and run Windows 98 Second Edition Setup in MS-DOS mode, the Windows 98 Second Edition fix is not migrated automatically, and you will be vulnerable to the problem described in the "Symptoms" section until you reinstall the fix.
IMPORTANT: There is no fix available for any version of Windows 95. The reason for this is explained in the following article in the Microsoft Knowledge Base:
246818 Windows 95 Does Not Support Hard Disks Larger Than 32 GB
Note that this problem affects only the protected-mode (graphical) version of ScanDisk.
The real-mode version of ScanDisk does not exhibit this problem. As a workaround, you can boot to a command prompt and run ScanDisk in real mode.
For additional information about Windows 98 and Windows 98 Second Edition hotfixes, click the article number below
to view the article in the Microsoft Knowledge Base:
206071 General Information About Windows 98 and Windows 98 Second Edition Hotfixes