I upgraded to 5.6 and am 250 photos into importing a 1,440-shot series of photos from Alaska. After shutting down Lightroom for the evening and resuming the next day, the catalog (on the left panel) shows my Alaska_2014 folder. Selecting Import from the Library options, the Alaska_2014 folder does not show in the right panel. Any thoughts on how this happened and what to do about it?
Can you post a screenshot of your import dialog? You should be able to scroll and drill down in that right-hand panel so that you can find any drive or file that's on your computer. So it's difficult to visualize the problem.