https://derflounder.wordpress.com/2014/10/25/new-filevault-2-enablement-option-in-yosemites-setup-assistant/ https://derflounder.wordpress.com/2014/10/25/new-fi

https://derflounder.wordpress.com/2014/10/25/new-filevault-2-enablement-option-in-yosemites-setup-assistant/ https://derflounder.wordpress.com/2014/10/25/new-filevault-2... It won't show up based on a number of criteria, your recollection may be correct but you may be running into this.