In the past, the beta version of the Apple system seemed to be the only developer, and the user rarely dared to try it. Now the situation is different, not only many users dare to the early adopters of their own devices, Apple also generous invite non-developer users to test the latest operating system. IOS Device Brush test version in case of problems, it is easy to brush back to the original version. But the MAC brush test version, will inevitably affect the work.
Therefore, how MAC users think of the early adopters, it is best to install the beta system on a hard disk partition, to avoid overwriting the original system. So even if the beta system affects the work, we can still go back to the original system. However, it is best to ensure that your Mac hard drive has a total capacity of more than 256GB to consider installing Yosemite to the hard disk partition.
First, we want to partition the hard disk. Open the Disk utility and select the partition. "Partition Layout" select "2 Partitions", then we adjust the size of the second partition, control around 50GB. Name self-fitting. Format Default "Mac OS extended (journaled)". Click "Apply" in the bottom right corner and wait for the following progress bar to complete.
After you have a good section, you can install Yosemite. Download the beta version of OS X 10.10 from our forum.
Here we review how to make OS X's startup USB drive. This is the method that every OS x new system releases, here we simply skip, specific can refer to our "teach you how to make OS X Lion boot U disk and use USB stick installation System".
After making the boot USB drive, the next step is the installation process. The installation of the MAC system is simple, here you just need to remember to install the Yosemite in our just separated from the hard disk. This will not overwrite the original system.
At this point, your Mac has two OS X systems installed, and the newly installed Yosemite is run by default on startup. If you want to go back to the original system, hold down option during the boot process until you have the option to choose the Startup disk.