How to partition your Mac to test OS X Yosemite

[iMore.com]

Installing Yosemite? It's a beta. Put it somewhere it's not likely to cause problems ? here's how​

Regardless of whether you're using the Developer Preview or the forthcoming public beta, bear in mind that OS X Yosemite is beta software. It's best not to install it as the primary operating system on your only Mac, so here are instructions for making a new partition to run it from.

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