I'm not sure if KR patches the same way that 2D does, but in 2D there is a patch folder in Program Files. Deleting any files out of that folder before starting up UO sometimes helps.

I've heard of other people having luck with an uninstall/reinstall of KR.

I've also read that if you haven't defragged your hard drive in a while, you might have luck uninstalling UO, defragging, then reinstalling it.

I don't think there's any sure-fire solution, though these ideas cover much of what I've seen in the past when this kind of problem comes up. Good luck!!