Hmmm . . . . first thing I think is security problem. So I move the copy from the CD to sit side by side with the one I just downloaded. That works just fine. So I copy and paste the internal URL and compare it to the blocked one. They're exactly the same but for the file name. Ok, I give up, what did they do to my machine?
A quick search on Microsoft turns up a new little button that you have to press before you can open certain sorts of files downloaded from the Internet Zone. Turns out that as of Security Update 896358, the Attachment Manager (new with XP SP2) marks CHM files as Untrusted.
Right-click to unblock file . . . . of course. . . . .obviously it's going to be as easy as clicking the button that's never been there before in any of the hundred thousand times I've looked at this dialog box. ;-)
As an added usability bonus, after you unblock the file, the button and it's helpful message vanish as mysteriously as they appeared.
You cannot open HTML Help files from Internet Explorer after you install security update 896358 or Windows Server 2003 Service Pack 1
File Under: Technology,