When I import I build 1:1 preview to help me filter through and weed out and the best images. The previews are discarded after a week to save disk space. However recently, after building and receiving confirmation of the build the images are still taking a couple of seconds to snap into focus when you zoom in. This tells that me that the 1:1 previews have not been built? I always run Lightroom on its own when filtering to make sure all the availabe processor speed and RAM is available. I am currently experiencing this with a folder full of 7,000 images from the last event. This is really slowing things down and not sure if just due to the heat or volume of images. I know some people prefer photo mechanic for weeding out before a lightroom import but I havent looked into that method yet. Any ideas?