The Serato DJ software update I need isn't yet compatible with El Capitan so they [Serato] recommends I go back to Yosemite.
MacBook Pro, OS X El Capitan (10.11.1)
Posted on Nov 17, 2015 4:58 AM
Q: How do I go back to Yosemite after already upgrading to El Capitan?
See: OS X El Capitan: Revert to a previous OS X version