There are quite a few steps involved in installation of Mac OS/X/El Capitan on a new partition and when you dual boot Yosemite on your Mac device, these are:
Enable access for assistive devices el capitan. Step 1. Select Open the Disk Utility plus choose the hard drive for which you want to partition (this is located at the left side set of choices on the screen and it is also referred to as the Macintosh HD).
Step 2. Create Click on the “Partition” tab from the Macintosh HD screen, and click on the positive (+) button in order to create an entirely new partition. Give it a name such as “Mac OS/X/El Capitan” and resize it.
Step 3. Apply Simply click on the “Apply” button to create an original partition, and you need to confirm after a request has been sent – do you wish to partition the target volume? Simply confirm and let the divider complete its process before you opt out of the Disk Utility.
Nov 24, 2015 Disk Utility received its first significant makeover in years as part of the recent OS X El Capitan update, and while Apple hopes the new design will make the app easier to understand and use, the new version of Disk Utility is missing at least one crucial function: RAID support. In the menu left of the “Disk Utility” window select the USB Drive. (The one you gave a specific name) In my case “OSXUSBInstall”. In the top menu bar from “Disk Utility” click “Edit” / “Restore”. In OS X El Capitan, Disk Utility has a different user interface and lost the ability to repair permissions due to obsolescence, create and manage disks formatted as RAID, burn discs and multi-pass format internal solid-state drives and encrypted external drives. ^^^^Thanks for that! I downloaded it, and so far it appears to be working fine with El Capitan PB 10.11.1. It even includes a Disk Permissions repair that has gone missing from Apple's new Disk Utility. Though that duty is restricted to only disks that have the El Capitan OS installed on them. And that's fine with me.
Step 4. Launch Simply launch the “Install OS/X/El Capitan” app and agree to the Terms of service (TOS), and you will see the drive selector showing up- simply click on the “Show All Disks” option.
Step 5. Install Simply select the OS-X-El Capitan (or whatever the name of the panel you created earlier on) and click on “Install”. Allow the Installation to complete and you will see the Mac rebooting automatically into your new OS/X/El Capitan when the whole process has been completed.
Step 6. Switch Now that your new OS-X-El Capitan is running on another partition, you can switch easily in-between two start-up drives on your Mac by rebooting your Mac while holding down the “Option” key. Holding downward the options key will definitely open the startup manager right before the OS X load on your Mac, and will give you the option of choosing between the version of the Mac OS you want to use or run. Rebooting and selecting between El Capitan and Yosemite is one of the best possible ways to switch, especially when you are still getting use to the new El Capitan.