in an attempt to access a truecrypt container, I stumbled about the prerequisite of setting up a loop device...

ncoghlan suggested in an earlier answer

When you run it as root, losetup -f will automatically create loop devices as needed if there aren't any free ones available. So rather than doing it yourself with mknod, the easiest way to create a new loop device is with sudo losetup -f. That approach will give you a free existing loop device if one exists, or automatically create a new one if needed.

My result of "sudo losetup –f" is

losetup: –f: failed to use device: No such file or directory

Searching for this message+losetup so far does not help.

Result of "lsmod |grep loop" is

loop                   28672  0

uname -r

  • 1
    sudo losetup -f requires an argument - a file to be set up as a backing storage for the loop device (the file containing your virtual disk/fs image)
    – Serge
    Jun 25, 2016 at 13:10

1 Answer 1


Serge's comment made me do my homework - study the man page in more depth than before. The solution was simply to enter in the shell


(without any arguments). Then, afterwards,

losetup -f

resulted, successfully, in


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .