MS Proxy 2.0 and Windows 2000 SP3

Installing Windows 2000 SP3 will break your MS Proxy 2.0 installation.

If you use the web proxy, you will receive an error "Invalid argument". Solving this can be done by not using the web proxy and let all the browsers use the winsock proxy.

However there is an additional problem. Installing SP3 on a computer running MS Proxy client will work, but installing MS Proxy client on a Windows 2000 SP3 computer, you will get a message saying that MS Proxy client 1.0 and 2.0 will not work with this version of windows! However I have experienced that it still does work, like it worked with Windows 2000 SP2.

Seems like Microsoft wants to ditch MS Proxy completely!
Microsoft Proxy Server 2.0