exFAT support on macOS seems to have some bugs because my external drives
with exFAT formatting will randomly get corrupted.
Disk Utility is unable to repair this at first, but the fix is this:
diskutil list to find the right drive id.
- You want the id under the IDENTIFIER column, it should look like
sudo fsck_exfat -d <id from above>. eg
sudo fsck_exfat -d disk1s3
-d is debug so you'll see all your files output as they're processed.
YES if it gives you the prompt
Main boot region needs to be updated. Yes/No?