Armadilloフォーラム

お世話になっております　芝です。
USBマウントについて教えてください

[root@armadillo440-0 (ttymxc1) ~]# usb 1-1: new full-speed USB device number 8 using ci_hdrc
usb 1-1: not running at top speed; connect to a high speed hub
usb-storage 1-1:1.0: USB Mass Storage device detected
scsi6 : usb-storage 1-1:1.0
scsi 6:0:0:0: Direct-Access Generic Flash Disk 8.07 PQ: 0 ANSI: 2
sd 6:0:0:0: [sdd] 4096000 512-byte logical blocks: (2.09 GB/1.95 GiB)
sd 6:0:0:0: [sdd] Write Protect is off
sd 6:0:0:0: [sdd] No Caching mode page found
sd 6:0:0:0: [sdd] Assuming drive cache: write through
sd 6:0:0:0: [sdd] No Caching mode page found
sd 6:0:0:0: [sdd] Assuming drive cache: write through
sdd: sdd1
sd 6:0:0:0: [sdd] No Caching mode page found
sd 6:0:0:0: [sdd] Assuming drive cache: write through
sd 6:0:0:0: [sdd] Attached SCSI removable disk

[root@armadillo440-0 (ttymxc1) ~]# mount -t vfat /dev/sdd1 /mnt
FAT-fs (sdd1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
[root@armadillo440-0 (ttymxc1) ~]# mount -t vfat /dev/sdd1 /mnt
mount: mounting /dev/sdd1 on /mnt failed: Device or resource busy
[root@armadillo440-0 (ttymxc1) ~]#

上記がログなのですが、busyになってしまい、マウントができない状態です。
この場合どうすればよいのでしょうか？
よろしくお願いいたします。