Originally Posted by Frogroast 
If I understand the posts about this issue, it doesn't seem to affect Adobe products, but it does affect iPhoto, Aperture, Bibble, and others.
Is this correct or not? I'm getting my K20D tomorrow and I can't wait to play. Last thing I want is to break it before I even get started
I updated my firmware and was immediately hit with a warning that I may need a plug-in to edit RAW images in Photoshop from LR (I use DNG). I just select "edit anyway" and it works fine. There is a box for "ignore this message next time" which I selected after getting this message several times. Now it's not an issue...or at least I'm not noticing any limitations or problems.
It may well be an actual problem with PEF format files since I have always used DNG.