
In the Format drop-down menu, choose MS DOS (FAT) (finally!).With the volume M selected in the sidebar, click Erase from the menu.Reformatting step 3 - reformat M as MS DOS (FAT):.Click Apply (after volumes are properly specified), click Partition (to create partitions), and then click Done.Enter a name (I called it T), size (16gb) and Format as MS DOS (FAT) (we're getting there).Click the Add button (+) appearing below the blue pie chart to add a new partition.With the volume M selected in the sidebar, click Partition from the menu.Reformatting step 2 - partition to create a volume T:.Click Erase button, and then click Done.Enter a name for the volume (I called it M).In the Format drop-down menu, choose Mac OS Extended (Journaled) (Yes!).Click Erase from the menu near/on the title bar.In the sidebar, choose the external USB drive.Reformatting step 1 - create a Mac OS formatted disk:.Launch Disk Utility from Applications folder.Insert the USB drive (you will need a USB-3.1 to USB-c adapter on the latest MacBook Air).Goal: To have 1 single USB drive for both dashcam and music (recordings) without a Y-splitter USB cable. Hence I resorted to the MacBook solution. I did start out with windows, was able to create the 16gb partition for TeslaCam, and was unable to format the remainder for music because of "cannot be resized since there is 33mb of used space" error. Inspired by the detailed post: How to Format USB into 2 Partitions for DashCam and Music by I have created this post for mac.
