% udevil --verbose mount /dev/sdd1
ROOT: /bin/mount -v -t exfat -o nosuid,noexec,nodev,noatime,umask=0077,uid=1000,gid=1000,iocharset=utf8,namecase=0,nonempty /dev/sdd1 /media/m10exfat
FUSE exfat 1.3.0
WARN: volume was not unmounted cleanly.
fuse: mountpoint is not empty
fuse: if you are sure this is safe, use the 'nonempty' mount option
mount exit status = 1
I've done a bit of debug, it's a problem of exfat 1.3.0, it doesn't pass the 'nonempty' option to the fuse library.
Downgrade exfat to 1.2.8 and you should be fine.
but after
# mkdir /media/m10exfat
all went fine.