Today I Learned that Acrobat Reader has a hook in Windows Explorer to pre-cache PDF files found in the current directory. This would be fine if (and ONLY if) I were on a machine that had rapid disk access or excellent file handing. I am not, and my system does not. So every time I see AcroRd32.exe show up in my task manager – every time I open up a directory with PDFs, basically – I get about 10 seconds of busy cursor. Distracting, annoying, unnecessary.