[SOLVED] umount said /dev/sdd is not mounted; yet lsblk said it is mounted to /run/media/ ?

Hmm ?!
Why it said /dev/sdd is not mounted ? yet lsblk said it is mounted to /run/media/user1/E.... ?

Code:$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 232,8G 0 disk
sda1 8:1 0 2G 0 part /boot
sda2 8:2 0 28,2G 0 part /
sda3 8:3 0 15,6G 0 part
sda4 8:4 0 187,1G 0 part /home
sdb 8:16 0 232,8G 0 disk
sdb1 8:17 0 232,8G 0 part /run/timeshift/backup
sdd 8:48 1 14,6G 0 disk
sdd1 8:49 1 9,6G 0 part /run/media/user1/ENDEAVOUROS
sdd2 8:50 1 5G 0 part
$ umount /dev/sdd
umount: /dev/sdd: not mounted.
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 232,8G 0 disk
sda1 8:1 0 2G 0 part /boot
sda2 8:2 0 28,2G 0 part /
sda3 8:3 0 15,6G 0 part
sda4 8:4 0 187,1G 0 part /home
sdb 8:16 0 232,8G 0 disk
sdb1 8:17 0 232,8G 0 part /run/timeshift/backup
sdd 8:48 1 14,6G 0 disk
sdd1 8:49 1 9,6G 0 part /run/media/user1/ENDEAVOUROS
sdd2 8:50 1 5G 0 partDid i did something wrong ?