Dual boot: OS X Mavericks and Mountain Lion?

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Dual boot: OS X Mavericks and Mountain Lion?

Hi there,

searching the internet I found a lot of video tutorials and discussions about the proper way to partition your hard drive so you can boot OS X Mavericks from your Mountain Lion system.

However, having installed Mavericks right after its release, I'm trying to install Mountain Lion as a partition on my computer. That's because I need to run some apps which aren't compatible with Mavericks.

As the Mountain Lion installer consistently tells me that it wasn't possible to run the system on my computer I wonder whether there's a way to boot both, Mavericks and Mountain Lion once you have installed Mavericks.

I'm grateful for any advice.

Thanks,

Lukas

MacBook Air (13-inch Late 2010), OS X Mavericks (10.9.2)

Posted on Mar 30, 2014 11:28 AM

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Answer 1

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a brody

Level 10

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Mar 30, 2014 11:30 AM in response to 1ukas

First of all, you must ERASE the hard drive to partition it so it is ready for both Mavericks and Mountain Lion. Then you install from your Mountain Lion installer in one, and Mavericks in the other. There are lots of guides to make a Mavericks and Mountain Lion self contained installer on USB Flash drives, or you can always boot off a hard drive that contains the said installer, and install from there.

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Answer 2

1ukas Author

Level 1

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Mar 30, 2014 11:42 AM in response to a brody

Alright.. So, in essence an "empty" partition besides the one running my operating system is useless unless I erase the latter and re-install both of the systems (being Mountain Lion first, followed by Mavericks this time), right?

I just hoped there was an easier way..

Thank you, anyway.

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Answer 3

ssls6

Level 4

2,879 points

Mar 30, 2014 11:59 AM in response to 1ukas

If you are trying to run the Mountain Lion installer from Mavericks, it will probably tell you it can't. I'm currently booted from Mountain Lion and tested the Lion installer and it told me no.

What you can do is make a Mountain Lion USB installer and boot from it. Now you can select the partition you created and install mountain Lion onto it. When the installer is finished (it will boot once at least), you'll be in Mountain Lion. To change back to Mavericks, open system preferences and select startup drive, there you can chose what starts at the next boot.

Instructions for making a Mountain Lion USB are here

http://arstechnica.com/apple/2012/07/how-to-create-a-bootable-backup-mountain-li on-install-disk/

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