I have a late 2011 15" MacBook Pro 2.2Ghz, 16GB ram which I just did a HDD replacement (512GB stock 5400) for SSD (256GB Samsung 840 non-pro). Everything went smoothly. I mounted ML to USB and ended up restoring my latest Time Machine Backup. No major complaints except for Aperture. For some reason, I lost all my Thumbnail and Previews for my pics (I have a library of 10K pics) and several of videos I obtained off of my DSLR won't load and show bizarre colored previews/thumbnails. The pictures work fine after thumbnail generates (which seems to happen instantly). CPU fan sounds like its screaming along and activity monitor confirms aperture process is utilizing high percentage of the CPU to generate previews (based on Aperture activity log). Is this typical? Was there something wrong with my Time Machine backup (I literally backed up right before I made the hard drive switch.