Well, it may not be mkexfatfs's problem...
I tried using gparted to re-format it FAT32 - Everything "completed
successfully" but same result on replug, all the files are there.
I tried deleting a directory on it, and "emptied the trash", unplug,
replug, directory is back.
[86799.359224] scsi 10:0:0:0: Direct-Access Generic STORAGE DEVICE
1404 PQ: 0 ANSI: 6
[86799.359637] sd 10:0:0:0: Attached scsi generic sg2 type 0
[86799.571164] sd 10:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9
GB/14.8 GiB)
[86799.573477] sd 10:0:0:0: [sdb] Write Protect is off
[86799.573481] sd 10:0:0:0: [sdb] Mode Sense: 21 00 00 00
[86799.575487] sd 10:0:0:0: [sdb] Write cache: disabled, read cache:
enabled, doesn't support DPO or FUA
[86799.588396] sdb: sdb1
[86799.593493] sd 10:0:0:0: [sdb] Attached SCSI removable disk
[86799.809090] FAT-fs (sdb1): Volume was not properly unmounted. Some data
may be corrupt. Please run fsck.
Also, I've tried clearing the dirty bit and I can keep running fsck and it
keeps saying it's dirty but per the dmesg output write protect is off.
I'm at a loss...
Richard