Upgrading an older Mac to El Capitan. Beware CPU hogging and over heating at first start up. It appears that Photos background activities coupled with Spotlight indexing are causing a lot of overheating and crashes on older Macs until both have completed initial set up. Try installing iStat Menus to run the fans faster and leave your Mac on for 24 hours after initial set up. As always, give me a call if you need help.