MAC OS is not designed to be down-gradable which you cannot downgrade it through an installer.

You will need to create a bootable install disk (Apple support).

If you decide MAC OS Sierra is not working out for you, you can downgrade it back to OS X El Capitan using the following steps.

The steps are as follows and it like a full OS reinstall.

If you’ve decided you’d rather return to OS X El Capitan, you can downgrade with just a few steps. It is a bit of a complex process, but if you follow the steps you’ll be back to your old setup.

1: Back up your Mac

2: Create a bootable drive of OS X El Capitan
3: Erase macOS Sierra
4: Reinstall OS X El Capitan
5: Restore data from an earlier El Capitan Time machine backup

1: Back up your Mac

This process will erase macOS Sierra from your hard drive entirely. That means any files, programs, or documents you’ve been working on while using macOS Sierra will also be erased if you don’t back them up first. Use an external hard drive or a cloud-based program like DropBox, OneDrive, or iCloud. If you don’t save these important files somewhere off of your computer you will lose them.

Step 2: Create a bootable drive of OS X El Capitan

Before you erase macOS Sierra from your computer, download OS X El Capitan from the Mac App Store. It should be in your purchase list, or you can simply search for it in the Mac App Store. You’ll need a copy of OS X El Capitan in order to downgrade from macOS Sierra.

Step 3: Erase macOS Sierra

1. Connect your Mac to the internet via Wi-Fi or Ethernet
2. Click on the Apple icon ()
3. Select Restart from the dropdown menu.
4. Hold down Command+R when you hear the startup chime and keep holding the keys until your computer reboots.
5. Click on Disk Utility in the OS X Utilities selector.
6. Click Continue.
7. Select your Startup Disk.
8. Click on the Erase tab at the top of the window.
9. Enter a name for the file to be destroyed (Like MAC OS Sierra or something).
10. Select Mac OS Extended (Journal-ed) from the format list.
11. Click Erase.

After the process is complete, quit Disk Utility from the drop down menu in the upper left corner of the screen to go back to the OS X Utilities selector.

Step 4: Reinstall OS X El Capitan

After you have erased MAC OS Sierra, you will want to reinstall an earlier operating system.

1. Click on Reinstall OS X in the OS X Utilities selector.
2. Click Continue in the El Capitan installation window.

OS X El Capitan will install like a standard update. You will agree to the licensing terms before the software reboots on your Mac.

Note: Depending on how old your Mac is, you may download an older version of OS X, possibly the one that originally shipped with your computer (especially if you end up in Internet Recovery Mode). If that happens, complete the installation of the older operating system (IE. Mavericks or Yosemite). Once the installation is complete, open the Mac App Store and download OS X El Capitan from your Purchased list.

Step 5: Restore data from an earlier El Capitan Time machine backup

If you have a recent backup of your Mac saved via Time Machine (which you should), you can use it to reinstall OS X El Capitan.

1. Connect your Mac to the internet via Wi-Fi or Ethernet
2. Click on the Apple icon ()
3. Select Restart from the dropdown menu.
4. Hold down Command+R when you hear the startup chime and keep holding the keys until your computer reboots.
5. Select Restore from Time Machine Backup in the OS X Utilities selector.
6. Click Continue.
7. Click Continue after reading the important information about restoring from a backup.
8. Select the Backup source for where your Time Machine backup is stored.
9. Click Continue.
10. Select the most recent OS X El Capitan backup on the drive.
11. Click Continue.

Your Mac will begin restoring from the Time Machine backup and then reboot. This process can take a while.

If you run into any problems while trying to downgrade your Mac operating system, let us know in the comments box or call our toll free #