The hard drive you selected in the previous step will display in Boot Camp Assistant, with one section labeled Mac OS X and the other labeled Windows. Use your mouse to click and drag the nub between the sections, to expand or shrink each partition, but don't click any of the buttons yet.
As you drag the nub, you'll notice that you can only shrink the Mac OS X partition by the amount of free space that is available on the selected drive. You'll also notice that you can't make the Windows partition smaller than 5 GB, although as I mentioned earlier, I don't recommend making it smaller than 20 GB.
You may also notice that there are two predefined sizes to choose from, via the two buttons located just below the display of the partitions. You can click the 'Divide Equally' button, which, as you might have guessed, will split your drive in half, using half of the available space for Mac OS X and half of the available space for Windows. This of course assumes that there's enough available free space on the drive to split things equitably. Alternatively, you can click the '32 GB' button, which is a good general-purpose choice for a Windows partition, again assuming you have enough free hard drive space to create a partition this size.
Set Your Partition Sizes
- Adjust your partition sizes
- Use the nub to select a custom size
- Use the buttons to select the pre-defined sizes
- Use the nub to select a custom size
- Click the ‘Partition’ button when ready.
Partitioning a drive usually takes some time, so be patient.
