StartOS working on iMac with Fusion Drive

Happy to report that I got StartOS installed on an old Intel iMac with a Fusion drive. If you aren’t aware, Fusion drive is an Apple proprietary solution that pairs a standard platter HDD with a solid state drive. I was able to use Disk Utility on macOS Recovery to erase the drive in a way that made it appear as two separate drives. Don’t remember the exact steps because it kinda happened by accident in a moment of tinkering just as I was ready to give up. :stuck_out_tongue:

Booted the iMac from a flashed USB with StartOS, installed on the HDD, and it’s running smoothly. Even wi-fi worked out of the box. I eventually plugged into eth and turned off wireless for better performance.

Hoping this post helps anyone with a Fusion drive Mac that wants to give it new life.


Thank you for letting us know about the great success :partying_face:

Hey I also have an iMac with 3TB fusion drive. So you partitioned the fusion drive so you can still boot the MacOS or does the StartOS run full time?

It’s fully dedicated to StartOS. I was done with the computer as a Mac

How did you get the mac to boot from the usb drive and install StartOS?

Depending on the mac you are using, you power all the way down. you press the power button and push and hold the key (Varies on different macs) before the apple appears on the screen. This will open up a window that shows you available disks. You select the one containing the flashed StartOS and install it on the drive. It will erase everything on the partition that you install it on.

To boot a Mac and choose a different startup disk, the process varies slightly depending on whether your Mac has Apple silicon or an Intel processor.

For Macs with Apple Silicon:

  1. Turn on your Mac and continue to press and hold the power button as the Mac starts up.
  2. Release the power button when you see the startup options screen, which shows your startup disks and a gear icon labeled Options. From here, you can choose a different startup disk.

For Intel-based Macs:

  1. Shut down your Mac.
  2. Press and hold the Option (⌥) key as you press the power button to start up your Mac.
  3. When you see the available startup disks, select one, then click the Continue button (on a Mac with Apple silicon) or the Up arrow (on other Mac computers).

This process allows you to boot from a network volume, a different disk, or another operating system by changing your startup disk temporarily. If you want to set a default startup disk for subsequent restarts, you can do so through the System Settings under General > Startup Disk, where you can select your preferred disk.

For more detailed instructions and additional startup key combinations for different purposes (such as accessing macOS Recovery or Safe Mode), refer to the official Apple Support pages on Mac startup key combinations and changing your Mac’s startup disk.