I did a complete reinstall of my OS on my MacBook Pro and I have a purchased CD of Adobe After Effects CS6 and it's not allowing me to reinstall. Having installed El Captain, I can't go back to a lower version of MacOS for my MacBook Pro. I have a project that I need to start working on and it requires me to use After Effects. AE was working prior to my doing the OS reinstall and I was to continue using AE CS6 that I purchased. Any suggestions? Thank you.
CS6 should run on El Capitan (with only a few problems) see this page. Besides the motion sketch problem that page mentions, the previews are a little funky until they loop once (but that's true for every version of AE before CC 2015 on Mac OSX 10.11.x).
What issues are you experiencing? AE CS6 must be updated to 11.0.4 to run on El Capitan.