If you are a new disk and wiping them to setup a DIY Fusion disk, how does the Mini carry on working afterwards... haven't you just wiped the OS? Without an optical drive, how can you clean the disks and still be able to reinstall an OS?

  • I found this, might help - discussions.apple.com/thread/5815647 Note, on a barebones machine, the OS will be downloaded by Recovery if there's no existing partition. It will download the OS the machine was first sold with. – Tetsujin Oct 17 '14 at 13:22
  • Can you go into more detail on "Recovery" - does it 'magically' get an OS from the web or is there a secret recovery partition? – Mr. Boy Oct 17 '14 at 13:28
  • On a fully installed system, there's a hidden partition, on a new drive it will use the magic of the interwebz to fetch the OS. See support.apple.com/kb/HT4718 – Tetsujin Oct 17 '14 at 13:32

You could also try Internet recovery

To do this boot your Mac while holding option+command+R Then when it loads (takes about 5 mins) go to disk utility and format your drive. After you have done that go back and select the option Reinstall OS X.

Hope this helps.


Without an optical drive, how can you clean the disks and still be able to reinstall an OS?

Simplest and cheapest way: create a bootable volume from the OS X Installer on a USB Stick.

2 days ago I used the (free) DiskMakerX to clone the 10.10.3 OS X Installer (it works also with older OS X versions) from AppStore to a USB Stick and used that bootable clone to start from it and install OS X on another volume. Everything worked fine.


This guide explains how to create a bootable USB installer, from the installer you'll be able to wipe the internal disk through disk utility before installation


I have been able to use OS X purchases from my App Store and use for clean install. Assuming you have gotten updates since lion was released? Go to your purchases and option + click the OS you want installed. The limit is naturally set so you cannot load an OS older then your machine.

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