Running a dual boot system with OS X and Windows 10 an ExFAT data exchange partition is useful.
But from time to time (after some months in my case) theExFAT partition is gone:
- OS X and Windows 10 list a raw partition instead of an ExFAT partition
Repair in OS X using the terminal:
- sudo su
- diskutil list
(this should display a “Microsoft Basic Data” partition with the size of the disappeared ExFAT partition;
the name column is empty; the identifier like disk0s3 has to be used in the next step) - fsck_exfat disk0s3
(replace disk0s3 by your ExFAT partition) - when asked by fsck_exfat to repair your “Main boot region” answer “y”
- diskutil mount disk0s3
(replace disk0s3 by your ExFAT partition) - now yourExFAT partition should be back in Finder
(which can be verified on the console with: ls /Volumes)
Details taken from this discussion.
Repair attemps on Windows could use chkdsk d: /f
(replace d: with the windows drive letter of your disappeared ExFAT partition;
use <windows key> + x to open an administrative console.)