. Click on the Erase button. Apple does not supply a freely downloadable copy via the App Store. Drag the mounted disc icon from the Desktop into the Source entry field. Prep this flash drive as follows: a. If you want a separate copy of Mountain Lion, then you will have to purchase and web page download it.
Move the copy into your Downloads folder. Rather it is through Internet Recovery should it be required. Click on the Partition button and wait until the process has completed. Double-check you got it right, then click on the Restore button. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Double-click on the SharedSupport folder.
Select the volume you just created this is the sub-entry under the drive entry from the left side list. Double-click on the Contents folder to open it. Open Disk Utility in your Utilities folder. The format process can take up to an hour depending upon the flash drive size. . .
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