In this tutorial, I will detail the processe to generate an installation from a USB flash drive.
First of all, make a backup of your important files to an external hard drive. The new installation of the operating system will erase all your data permanently.
The first thing to do is get a copy of the OS, which must be download without charge from the Apple Store. Download now it you have not done so.
Note that there are two versions, one for Desktop and one for the Server. We will use the Desktop version.
The second thing we have to prepare is a USB flash drive with at least 8 Giga Bytes capacity.
The third thing to do is download the application DiskMaker. We will use this application to generate the installation of OS X Yosemite in USB flash drive.
The link to download the DiskMake is this: http://diskmakerx.com/. The version that was available when I wrote this tutorial wasDiskMaker X 4.0b4.
After downloading, simply install as the standard Mac applications.
The installation process is very simple and does not present difficulties, simply drag the DiskMaker application icon for the MacBook application folder as show with arrow in the previous image.
Is everything is correct, you will see the shortcut to DiskMaker pressing the F4 key on your keyboard.
The fourth thing to do is connect the USB flash drive that will be used to generate the installation boot in any of the USB ports on your MacBook.
The fifth thing to do is run the DiskMaker. Make sure if you previously connected a USB flash drive, and obviously download the OS X Yosemite installation package is done.
Note that the DiskMaker X will give you more then one option of OS X, but in our case, we will install the 10.10 version. Just choose this option to continue.
After choosing the 10.10 version and click, the screen above will be displayed as confirmation that OS X Yosemite was detected on your hard drive and is ready for use. You must click Use this copy.
As the USB flash drive is already connected to your computer, DiskMaker X detects and asks if you want to use this USB flash drive to generate the boot installation, simply click An 8 GB USB thumb drive.
Made the choice of USB flash drive, the DiskMake will show you a screen like the one shown above. Is only confirms that there is an OS X that can be used to generate the boot on USB flash drive. Click Choose this disk.
After that, a warming message warms you that all data will be lost is displayed, click Erase Then create the disk.
This is one of the last screen that will be displayed during the installation process. This process usually take a while. Be patient and wait finish the whole boot generation procedure.
One thing you can do right now is to monitor the USB flash drive, leaving open the Finder and you can view the creation of the files.
This is the last screen, ending the installation creation process in the USB flash drive.
The sixth thing to do is run a boot on your MacBook with the USB flash drive connected to a USB port, and press during boot the ALT OPTION key to appear for you to select which device you want to use to boot. Select the USB flash drive and install OS X Yosemite normally.
I hope this tutorial helps you. I'll soon add a video with all the steps commented here.
Please visit my YouTube Channel - YouTube's Marco Maddo