How to make clean install ML on USB3 external

Discussion in 'Mac mini' started by propower, Jun 19, 2013.

  1. propower macrumors 6502a

    Jul 23, 2010
    Hey all,

    I have the 2012 i7 Mac mini with an apple 256G SSD inside. I want to make a clean install of mountain lion on an external SSD to do some debugging of an audio system but I can not get it to work. I can clone my system to the external but I really want an OSX only clean install...

    I have tried...
    1) Boot from recovery disc on internal drive and do a operating system install on external. It gets all the way to the end of the install and then goes to reboot. Every attempt ends in the screen going blank and a message coming up that the machine had shutdown and will restart (in four languages)... loop --- loop -- loop

    2) Cloned the system to external -- boot to recovery partition of external -- disk utility to erase main partition in external -- do clean install -- same result as above

    I am stumped!!!! The external is a Samsung 830 drive in a Silver River 5G USB3 case. Works perfect on cloned drive

    Any help appreciated!

  2. opinio macrumors 65816

    Mar 23, 2013
    A few options that might work, although there is no reason why they would work other than what you have done. In no particular order (and totally unconnected with each other):

    - Internet recovery: CMD-Option-R on startup - may work better for a fresh install.

    - Booting from a USB recovery disk. Apple has a downloadable app that you can copy to a disk and boot from it.

    - Did you format the drive?

    -Try unplugging your intenal SSD to force the external as the only SSD available. You could boot into a recovery option either via internet recovery or a USB boot disk noted above.

    -Try another SSD controller connection. I.e. a different USB3.0 dock or something. Or firewire to T-bolt connection if you have one. It could be your external enclosure is no good for boot up. Although it did work on the clone.

    Anyone of the above options has not special reason why it would work but it is an alternate option to what you have tried.
  3. propower thread starter macrumors 6502a

    Jul 23, 2010
    The answer was a little weird but simple...

    I have an Apple TB monitor and an HDMI monitor

    As soon as I unplugged the HDMI monitor everything started working perfectly.

    Thanks - hope this helps someone else...

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