sudo fsck_exfat -q /dev/disk1s2
QUICKCHECK ONLY; FILESYSTEM DIRTY

sudo fsck_exfat -gd /dev/disk1s2

/* results */
0 clusters were marked used, but not referenced

0 clusters were marked used and CLUST_BAD

0 clusters were marked free, but referenced

(S,"Rechecking main boot region.",0)

(S,"Rechecking alternate boot region.",0)

(S,"The volume %1$@ appears to be OK.",1)

sudo fsck_exfat -gdy /dev/disk1s2

/* results */
fsck_exfat: Could not update main boot region: Bad file descriptor

sudo fsck_exfat -q /dev/disk1s2
QUICKCHECK ONLY; FILESYSTEM DIRTY