I have erased my Mac Mini and now I am presented with the Recovery screen where I can use Disk Utility, Reinstall, etc.

Nothing works!

Disk Utility claims it cannot unmount the primary HDD, despite the "mount" option being greyed out, which suggests it's not mounted. Disk Info says "Writeable: No".

When I attempt to reinstall, I get to the HDD selection screen but the only option is to select the Recovery HDD, which is also greyed out LOL!

The Mac Mini came with no CD (ordered from Apple). Everything was preloaded. Apple website suggests downloading the MacOS to create a bootable USB... But you need a Mac to do so!!!

Don't know what else to do and would be really grateful if anyone could share what I can do.

  • 3
    Try the Internet recovery (not local) ...Command (⌘) – Option (⌥) – R – Ruskes Nov 19 '18 at 7:42
  • BTW if the "mount" button is greyed out then it is either already mounted or there is nothing to mount, EG you need to create a partition and format it properly. – Steve Chambers Nov 19 '18 at 14:49

You need to create a new partition using Disk Utility that you can use for installing macOS.

You'll need somewhere to store your system, and without a partition (besides the recovery partition), you'll have no such place. That's why you have no choices when you run the installer.


I found this useful article on the matter:

It is possible to restore a Mac without a recovery partition, but it can be tricky (especially on older Macs). You have a few approaches available:

Use Internet Recovery to reinstall OS X on Mac with a missing recovery partition.

Create a bootdrive to install a copy of macOS from.

Use your Time Machine backup as your start-up drive.

You may also be able to create a Recovery partition.

  • The OP has a recovery partition, so that's not the case here. – jksoegaard Nov 19 '18 at 8:07

Follow this guide: https://support.apple.com/en-au/HT204904

Use Option-Command-R, as this will boot both to Internet recovery mode, and will install the latest OS compatible with your system.

You will need to ensure you have a partition configured on your HDD before you can perform the installation. Use this guide to help you: https://support.apple.com/en-au/HT208496

When formatting the internal HDD, you will most likely need to use macOS extended journaled formatting with the GUID partition map scheme.

Be very careful not to interfere with the recovery partition, or it will make it MUCH harder to get your system running without an installation DVD.

When you have your HDD partitioning issues sorted out, you should be able to more easily either restore a time machine backup, or to reinstall the macOS from the main recovery screen.

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