(Note: Snow Leopard will not install on some newer Macs made after mid-2011, but some of these Macs will run Snow Leopard although Snow Leopard will not install - there are ways (by using older Macs) to get Snow Leopard running on some newer Macs without installing. Make certain that your Mac is compatible with whichever OS you plan to upgrade to. For Lion (OS 10.7) or Mountain Lion (OS 10.8), you need to go to the online Apple Store to purchase and get info on how to download. From there you should be able to download and upgrade to the most current OS (currently OS 10.9 – Mavericks). Go to the Applications folder and open “App Store”. Who this affects: Keeping in line with Apples upgrade policy, OS X El Capitan is free for all users running at least OS X 10.6.8 (Snow Leopard). If you wish to upgrade FROM Snow Leopard, make sure you are running OS 10.6.8. Afterwards you can start up from your old OS or Snow Leopard by pressing OPTION key during startup. Snow Leopard 10.6.7, Lion, Mountain Lion, Mavericks and Yosemite all have the Mac App Store, which is a requirement for the digital download delivery mechanism to install OS X 10.11 El Capitan. Alternatively, install Snow Leopard to a empty partition that has been formatted as Mac OS Extended (Journaled) with the GUID option. Before upgrading to El Capitan, the Mac will need at least 8GB of available hard disc space and be running Mac OS X 10.6.7 Snow Leopard, or later. however, I recommend making a complete bootable backup before doing so in case something goes wrong during installation, such as power outage. Many people simply upgrade directly over the old OS installation. After installing, do Software Update (under the Apple Menu) to bring Snow Leopard up to OS 10.6.8. If your Mac does not have an optical drive, the DVD has instructions on doing a remote install from another Mac on the same network.

Then purchase the Snow Leopard install DVD from the Apple Store. (If the word “Intel” appears anywhere beside “Processor” you have an Intel-based Mac.) To find out go to Apple Menu and select “About This Mac”. If you wish to upgrade TO Snow Leopard (OS 10.6), make sure you have an Intel-based Mac (Snow Leopard will not run on a PowerPC processor) with at least 1GB of memory and has Mac OS 10.5 or earlier.

Upgrade from snow leopard to el capitan