I'm using Lightroom 3.6 on a Mac. I recently bought a new computer and transferred everything over to the new 27" iMac. Lightroom appears to work fine and when I insert a card to do an Import, the thumbs show up. But when I click Import, I get a message that it can't import the pictures because it can't import them, I use a Sony A550 for raw pictures with the .ARW at the end. Any suggestions?