Inspired by the detailed post: [V9] How to Format USB into 2 Partitions for DashCam and Music [Windows] by @SomeJoe7777, I have created this post for mac. 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. Hence I resorted to the MacBook solution. Goal: To have 1 single USB drive for both dashcam and music (recordings) without a Y-splitter USB cable. System data: macOS Mojave 10.14.4 Sandisk Extreme Go USB 3.1 128gb Follow these steps: Insert the USB drive (you will need a USB-3.1 to USB-c adapter on the latest MacBook Air) Launch Disk Utility from Applications folder. Reformatting step 1 - create a Mac OS formatted disk: In the sidebar, choose the external USB drive. Click Erase from the menu near/on the title bar. In the Format drop-down menu, choose Mac OS Extended (Journaled) (Yes!). Enter a name for the volume (I called it M). Click Erase button, and then click Done. Reformatting step 2 - partition to create a volume T: With the volume M selected in the sidebar, click Partition from the menu. Click the Add button (+) appearing below the blue pie chart to add a new partition. Enter a name (I called it T), size (16gb) and Format as MS DOS (FAT) (we're getting there). Click Apply (after volumes are properly specified), click Partition (to create partitions), and then click Done. Reformatting step 3 - reformat M as MS DOS (FAT): With the volume M selected in the sidebar, click Erase from the menu. In the Format drop-down menu, choose MS DOS (FAT) (finally!). Click Erase button, and then click Done. I haven't tried but combining 4.1-4.3 as part of 3.3 should work as well. Create the folder TeslaCam in volume T. Use the USB stick in one of the 2 USB drives in the front cubby hole. The dashcam sign should pop-up near the right-top corner of the display. Results: Before I tested it out, I loaded some music onto the M drive. Everything worked as expected. Clips from the front dashcam, the left and the right repeater cams in 1 minute interval are available in the /T/TeslaCam/RecentClips folder. After returning from the test drive, I "downloaded" the last 10 minutes of the recording by pressing the dashcam icon. This gets saved into the /T/TeslaCam/SavedClips/DateXYZEtc folder. If you keep pressing the dashcam icon on the display for a few seconds, you will see a tiny expanding circle indicating that the recording has stopped. I did this and stop playing the music before I pulled out the stick. I don't seem to have any lost or corrupt data in my USB. Has been tested with music playing (from the USB) all the while. I hope this helps!