Contrary to initial optimistic predictions that upgrades to Windows Me would prove to be uncharacteristically smooth, incompatibilities with popular applications are starting to surface.

As such, experts are urging PC users to heed the old adage that it takes three attempts before Microsoft get its’ operating systems right.

Although Windows Millennium Edition is built on the Windows 9x kernel, not all Windows 98 software runs properly on it, particularly anti-virus and personal firewall programs.

Among the Windows 98 programs that have had problems with Me are personal security tools such as Symantec's Norton Internet Security 2000, Norton Personal Firewall 2000, and Network Associates McAfee PGP Personal Privacy.

Microsoft says the Windows 98 versions of these applications might be having problems because of at least two key changes in Windows Me that weren't anticipated by all vendors.

One is that Microsoft no longer supports DOS for Windows Me users. Real Mode DOS is a character-based operating system, and all earlier versions of Windows 9x allowed access to it so users could run non-Windows DOS programs.

Also, the new OS uses the Windows 2000 TCP/IP networking stack instead of the one from Windows 98.
Either way, you may need to upgrade antivirus and firewall software to run smoothly with Windows Me.

Upgrades are available for Norton Systems Works 2000, Internet Security 2000 and Personal Firewall 2000, and McAfee VirusScan 5.

If you run Dr. Solomon's Anti-Virus or PGP Personal Privacy, you'll have to delay upgrading to Windows Me until the applications vendors release updates.