View Full Version : [ubuntu] Getting request to authenticate loop device /dev/loop`12

April 30th, 2018, 02:56 PM
One of my PC's that is just upgraded to 18.04 LTS is now asking to authenticate loop device /dev/loop 12 when I open a file I have downloaded.

Everything works once I authenticate, but what is going on.

Thank you,


May 1st, 2018, 01:29 AM

what is the output of the command:

df -kh ?

I suppose that you have snap packages installed in your system.

In any case I would try to change the permissions of the /dev/loop* and see what I will get.


May 3rd, 2018, 02:01 AM
john@john-MS-7846:~$ df -kh
Filesystem Size Used Avail Use% Mounted on
udev 3.8G 0 3.8G 0% /dev
tmpfs 784M 1.7M 783M 1% /run
/dev/sda5 72G 67G 1.9G 98% /
tmpfs 3.9G 30M 3.8G 1% /dev/shm
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup
/dev/loop0 87M 87M 0 100% /snap/core/4486
/dev/loop4 13M 13M 0 100% /snap/gnome-characters/69
/dev/loop1 1.7M 1.7M 0 100% /snap/gnome-calculator/154
/dev/loop2 87M 87M 0 100% /snap/core/4407
/dev/loop3 21M 21M 0 100% /snap/gnome-logs/25
/dev/loop6 22M 22M 0 100% /snap/gnome-logs/31
/dev/loop8 141M 141M 0 100% /snap/gnome-3-26-1604/59
/dev/loop7 3.8M 3.8M 0 100% /snap/gnome-system-monitor/39
/dev/loop5 13M 13M 0 100% /snap/gnome-characters/86
/dev/loop9 2.4M 2.4M 0 100% /snap/gnome-calculator/167
/dev/loop10 83M 83M 0 100% /snap/core/4327
/dev/loop11 3.4M 3.4M 0 100% /snap/gnome-system-monitor/36
/dev/sda6 93G 11G 78G 13% /media/MyDocuments
/dev/sda7 53G 69M 50G 1% /media/MyChemistry
/dev/sda1 215G 100G 115G 47% /media/OS
tmpfs 784M 120K 784M 1% /run/user/1000

So, is there really a loop 12?


May 3rd, 2018, 08:06 AM

all these /dev/loops are corresponding to snap packages that you have installed. The fact that they are 100% full is pretty normal. From the output of the command I cannot see any /dev/loop/12, yet I can see duplicate packages including 2 versions of gnome-system-monitor. Similar case can be found here:

I do not know if this would help you, but you could try to remove this package, since its harmless using:
sudo snap remove gnome-system-monitor

and see if you get the same error. If this does not work you could update your snap packages using:
snap refresh

and see what you will get.