I use a Mac Pro 2x2.66 Dual Core Xeon tower with 15 GB Ram and OS 10.7.5. CS6 (always the latest update) is becoming very "buggy". It starts slowing way down, then does things like sharpening changes in ACR disappear when the photo is opened as a file in Photoshop, and other random little failures. Resetting preferences in both Bridge and Photoshop doesn't fix it. Also repairing Disk Permissions had no effect. The only thing that works is re-installing CS-6. I have to do this now about every two months, which is a pain. Any thoughts about what might be going on and how to fix it? Thanks!!
Check the Camera RAW preferences. "Sharpen previews only" is a setting in Camera RAW, so if you loose sharpening when the photo is opened in Photoshop, it may simply be a preference setting that was changed by mistake.