In Linux Mint 18.2 when I choose "Open With Disk Image Mounter" in a right click menu on an .img file I get following error:

Unable to mount OS

Error mounting /dev/loop1 at /media/mint/OS: Command-line `mount -t "ntfs" -o "uhelper=udisks2,nodev,nosuid,uid=999,gid=999" "/dev/loop1" "/media/mint/OS"' exited with non-zero exit status 21: ntfs-3g-mount: mount failed: Permission denied

("OS" is a label of a drive from which this image was created.) I have another .img file (also with NTFS in it) and I receive similar error when I try to mount it. Both files were created with a built-in Linux Mint "Disks" utility. If it helps, they are both 100Gb+ in size and have brackets in their names.

How do I fix this error? Or maybe there is a way to mount or view their contents with different tools?

  • Are you prompted for authentication when you try to mount it? Have you tried mounting it from the command line as root? Jun 10, 2018 at 13:24
  • @NasirRiley No, I'm not prompted for authentication. I tried to copy command line from this error message into terminal adding "sudo" before it, but I still get an error: "> Failed to read bootsector (size=0) Failed to sync device /dev/loop1: > Input/output error Failed to mount '/dev/loop1': Invalid argument The > device '/dev/loop1' doesn't seem to have a valid NTFS. Maybe the wrong > device is used? Or the whole disk instead of a partition (e.g. > /dev/sda, not /dev/sda1)? Or the other way around?"
    – Cint
    Jun 10, 2018 at 17:31
  • Create a mountpoint such as /mnt/img and then try this: mount -o loop /path/to/file.img /mnt/img You may get a message of mounting read-only but it should mount the img file Jun 10, 2018 at 18:35
  • Is the image of a filesystem or a disk? You can check with file /path/to/image If it's a disk image, you can use kpartx to create block device files from the partitions within the image; Then you can mount the correct block device. You can also use the libguestfs shell to mount a disk image. Jun 10, 2018 at 21:10

1 Answer 1


It looks like you are trying to mount a disk image (with the image including a partition table and possibly multiple partitions instead of just one partition). Try using the loop module with

sudo losetup -f file.img

The NTFS formatted partition(s) should then show up in the file manager.

You may need to allow partitions on the loop device explicitly (see How to create a formatted partition image file from scratch?).

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