It didn’t forget them; it’s just double-checking with you. The developer responsible for CD autoplay in Windows XP SP2 explained it to me. There were two problems with the way Windows XP handled CD autoplay. First, when you installed a new program that included CD autoplay capability, many users didn’t know where in the UI to go to select that new program as their default CD autoplay program. If they had previously selected a program and ticked “Always perform this action”, there was no easily-discoverable way to undo the “always” flag to make the dialog reappeared and allow the user to select the new program instead. Second, many programs, upon installation, secretly hacked the undocumented CD autoplay settings in order to set themselves as the default CD autoplay handler, gleefully overriding the user’s previously-stated preference. Because these programs egotistically believed themselves to be the coolest most amazing program ever written in the history of mankind. In other words, the two problems were, “I just installed this program and I want it to be the CD autoplay program” and its converse “I just installed this program and I don’t want it to be the CD autoplay program”. Windows XP SP2 introduced new behavior related to CD autoplay in an attempt to address these problems: When it sees that a new CD autoplay handler is available, it shows you the CD autoplay dialog one more time. This gives you a chance to (a) pick that new program you just installed, or (b) un-pick that program you just installed (if it was presumptuously rude enough to set itself as your default). The first time you insert a CD into your computer after upgrading to Windows XP SP2, you will also get the CD autoplay dialog. This is a “better late than never” dialog to cover for any handlers that were installed before you upgraded to Windows XP SP2.

What’s the moral of the story? Whereas in the old days, you only had to worry about helping other programmers interface with your feature, in the new software landscape, you also have to worry about stopping programmers who are trying to abuse your interface.