I went back and traced the U98SESP3 installation on my computer. I'm running Windows 98 SE from the last MSDN distribution for 95/98/ME. U98SESP3 installs updated DUN system files, but does not register the new adapter if the old adapter is not already installed and configured. To reproduce, click: Control Panel Network Configuration, Add Adapter, Add Manufacturers, Microsoft Network Adapters, Microsoft Virtual Private Networking Adapter OK (and the dialog silently fails) This seems to happen because U98SESP3 breaks the "Virtual Private Network " component dependencies for Windows Setup during the SP3.CAB override. The usual dependencies for "Virtual Private Network" disappear, which are "Dial-Up Networking", "ISDN Configuration Wizard", and "Telephony Support". A silent dependency on "Dial-Up ATM Support" is also added, because if the registry changes for that component don't happen, then the new adapter is not registered. Toggling the entire "Communications" section or running dun14-se.exe resolves the adapter registration glitch after running U98SESP3. Does this project have a repo for developers? The changelog doesn't explain how or why things happened, and having the change history would make it easier for me to submit a patch instead of a bug report.