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How to install two copies of Mac OS X on a Hard Drive?

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How about some accepted answer love? – peelman Feb 16 '11 at 17:50

Partition the drive...install OS A to one partition, OS B to the other. Hold option when booting to select which OS you want to boot from.

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Repartition the hard drive with Disk Utility and then just install Mac OS X on the new partition.

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i prefer to install 2nd MacOs on external disk (preferably with Firewire 800 connection), unless my machine has got more than one disk.

you didn't mention your computer model and the MacOS you want to install. MacOS 9 and 10? 10.5 and 10.6?

you didn't mention why you want to install 2 MacOS. do you want to run a "repair" utility from the 2nd OS?

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Use VirtualBox and run one virtualized inside the other. The virtual one can be kept on your main HD, an external drive, USB key, etc.

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