SIMPLE FIX: USB SHOWING FULL BUT NOTHING ON THE USB (for Mac)

I hope this helps someone. So simple once I knew what to do. I had a 32 GB USB that I was using to transfer data from a Macbook Air to a desktop iMac. After transferring all data, deleting the data on the USB, emptying the trash, it showed I only had 808MB available on the USB drive:

1) Insert USB into the drive

2) Click on finder

3) Top ribbon Menu Bar > Go>Utilities

4) Double click on Disk Utility

5) On the left side of the page in Disk Utility in gray, click on the USB

6) Go to the top of the page on the right (you'll see volume, partition, erase, restore, unmount, info)

7) Click on Erase

8) If you are using a USB, click on ExFat - If you are using an external hard drive, click on Mac OS 9) Extended.

10)Erase

Done