Lightroom 3.6 on a Mac running OSX 10.7.2 can import photos fine. But the folder containing those photos vanishes from the 'Folders' sidebar upon relaunching Lightroom. The photos are still accessible in Lightroom and the folder containing them is still visible in Finder, but that folder doesn't show up in Lightroom. This happens when importing in any method, including Copy, Move, or Add. I've tried fixing permissions on local drives and repairing external drives.