Process Monitor showed me that IE 9 accesses every time it loads on my system, which makes it have a 1- to 2-second delay every time it loads. (I tested this by removing my fonts -- it loaded much more quickly.)
It gets a little annoying, because it's the best handler I have for MHT files, so I don't want to switch to something else.
Is there any way to make it avoid doing that? (The "Hide Fonts" feature in Windows 7 doesn't work.)