Preview Does Not Work
I'm having an issue where previewing simply does not work. Sometimes frames will turn green as it plays though, sometimes only one frame will show green at at time. Even if it appears that it's rendering and all keyframes turn green, once it gets to the end of the work area, the green bar disappears completely and it does not play back. I've tried restarting my computer, importing my project into a new file, purging the caches, etc.
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Nate V commented
Update: it's working now with a different project. My problem project contained around 50 video clips, but I'm not sure why that would cause this particular problem, especially after purging all disk cache.
A similar issue occurred in my AE and going back to version 13.0 (2014) helped.