Issue: RED files may not import, and if they do import they will stop displaying frames after a short time
This problem only appears in After Effects CS6; it does not happen in After Effects CC (12.x) or After Effects CC 2014 (13.x).
You can use Adobe Media Encoder or Adobe Prelude to transcode footage to another format that does not have this issue.
You can reinstall an earlier version of Mac OS X which does not cause this issue. For details, see this article.