Installing Mountain Lion on an external drive

[eVasilis]

Hi all, I am running HS 10.13.4 and I have been trying to install Mountain Lion on en external drive so I can use dvd studio pro. So far, all I have tried has failed. Whenever I restart form the installer USB stick all I get is a message that the mac was not not shut down properly and the mac boot again with High Sierra. Any ideas?

Thanks!

 

[chrfr]

Hi all, I am running HS 10.13.4 and I have been trying to install Mountain Lion on en external drive so I can use dvd studio pro. So far, all I have tried has failed. Whenever I restart form the installer USB stick all I get is a message that the mac was not not shut down properly and the mac boot again with High Sierra. Any ideas?

Thanks!

Are you sure your Mac is compatible with Mountain Lion? What model is it exactly?

 

[eVasilis]

Are you sure your Mac is compatible with Mountain Lion? What model is it exactly?

Apologies, I forgot to mention that I own a 12-core 2010 Mac Pro...

 

[Fishrrman]

There is a Mac Pro specific forum here at MacRumors.
I suggest you repost your question there...

 

[MSastre]

Do you by any chance have a cloned drive of your old system? That is the easiest way to get back. DVDSP will still work on later OSs, just not HS. I have run it on El Capitan, and even Sierra may work, but have not tried yet.

 

[eVasilis]

Do you by any chance have a cloned drive of your old system? That is the easiest way to get back. DVDSP will still work on later OSs, just not HS. I have run it on El Capitan, and even Sierra may work, but have not tried yet.

I'm afraid not. If I did I'b be more than happy. Thanks for your reply!
[doublepost=1524518999][/doublepost]

There is a Mac Pro specific forum here at MacRumors.
I suggest you repost your question there...

Thanks, I posted my question there too.