Three way OS X install conundrum

[R3k]

Hi Guys.

Im booted into Yosemite on a 2013/14 Mac Pro, and I'm trying to install Mavericks onto an external USB volume that currently has a Mountain Lion on it.

Unfortunately the Mavericks installer gives me the error "Install OS X application is too old to be opened on this version of OS X"

Is there any way I can accomplish this task?

I can't seem to boot into the Mountain Lion volume on the Mac Pro btw, guess its too old an OS?

 

[DeltaMac]

Make a bootable installer from your Mavericks installer app.
Apple has a page to tell you how to do that through the terminal.
Or, a simpler method is to use an app to create a bootable partition or external drive.
I like to use an 8GB flash drive, or just a separate partition on an external hard drive. Here's an app that I have used successfully for a couple of years: http://diskmakerx.com/whats-this/

Mavericks will be fine on your 2013 MacPro, but not Mountain Lion. The new MacPro shipped with Mavericks, but Mountain Lion is too old.

 

[R3k]

Make a bootable installer from your Mavericks installer app.
Apple has a page to tell you how to do that through the terminal.
Or, a simpler method is to use an app to create a bootable partition or external drive.
I like to use an 8GB flash drive, or just a separate partition on an external hard drive. Here's an app that I have used successfully for a couple of years: http://diskmakerx.com/whats-this/

Mavericks will be fine on your 2013 MacPro, but not Mountain Lion. The new MacPro shipped with Mavericks, but Mountain Lion is too old.

Great, thanks for your advice. Ill look into this

 

[R3k]

Yeah this did the trick. Had some separate issues doing the install on an external USB drive, but sorted things out when I used a FW800 chassis instead.

Ty