I encounter problems when using H264 quicktimes in my timeline, as well as .MXF files from the Sony C300.
Immediate crashing when scrubbing the timeline.
When scrubbing the timeline and letting go of the cursor on the timeline the frame goes instantly grey, black or green.
Displays frames from random places in the timeline.
It renders grey, and basially looks like a corrupt file.
Crashes and or fails at specific frames on the timeline.
RAM previews resulting in '...2 or more frames' error'.
I also get 'An output module failed...1610153464...' error message when the renders crash.
I get a random combination of the above on most projects, all of which were created in CS5 and opened in the new CS6.
I'm using a recently new iMac with 12Gb RAM, Mountain Lion.