Add Partition to USB Drive on a Mac

Step One

Add a USB drive to the USB port on your Mac​.

Step Two

Open the app called "Disk Utility."

Step Three

Select the USB drive on the bottom left side of the menu pane. Note: Select the drop down menu at the top left (next to "Disk Utility") and select "show all devices."

Step Four

Select "erase" at the top left to format the disk (make sure there are no files on the drive or you will lose them). 

Step Five

Select "Format" and then "Mac OS Extended Journaled." Under "Scheme" select GUID Partition Map.

Step Six

Select "Partition" at the top menu bar. Select the (+) symbol beneath the pie chart to add another partition. Note: One partition comes with drives by default. Use the Pie Chart to select how much space you want to dedicate to the partition.

Step Seven

Select "Apply." On the left menu bar, you wil notice that you USB drive now has two partitions. 

Caution: You must make sure to select the USB drive and not your hard drive by mistake or you risk losing the files you have on your computer's hard drive.