Hi there,
Not sure if this will help you at all, but I thought I’d share my experience with resolving this situation.
I’m running CS6 on a dual core Xeon Mac Pro, 12 GB Ram
In the after effects menu there’s the option for clearing the cache (which i had set to max size of 93 GB). I used this option and got confirmation telling me this was completed and so I assumed that my cache was empty when I was getting this problem.
However, when I ran omni disk sweeper to find where all my hard drive space had gone, I stumbled upon the cache file locations, which was still full of 93 GB of cache files. (User > Library > Preferences > Adobe > After Effects > 11.0)
Clear this folder manually, restart your computer performing a PRAM reset (hold ctrl+cmd+p+r during boot up until you hear the chime for the second time) and you should find that you’ll be able to render quicktimes without turning off multi processing or clearing the cache in the secret menu.
I can only assume that clearing via the after effects menu didn’t work because of a permissions issue on my computer – I had recently run a ‘repair permissions’ from disk utility, which I suspect might have interfered with After Effects.
Martin Hickford | Freelance Video Editor & Multimedia Designer for TV, Film, Commercial & Promo. Technically an adult.
https://www.shootfirsteditlater.com