A file may have gotten corrupted by the Tesla software or the drive may be full.
Make sure you are properly removing the USB drive from the Tesla and from your computer. If you delete footage from the drive on your computer, make sure you empty the Recycle Bin (Mac) or Trash (PC) PRIOR to removing the USB drive. Failure to do so can leave temporary files that can corrupt the drive and make it not readable by your Tesla.
Here are the steps to get you up and running again: