My friend gave me a USB with some tutorials that are iso formated When I try to open them on my Ubuntu 18.04,I got this

enter image description here

If I choose to start restoring will it erase all the other content on my 500GB disk or not?

  • 12
    On a side note: the default action for opening ISO files in Ubuntu is to suggest the user to erase their entire hard drive? Talk about user friendliness...
    – Przemek D
    May 21, 2019 at 9:39
  • @PrzemekD On my Xubuntu 16.04, the default action is to view it in Archive Manager.
    – Melebius
    May 21, 2019 at 9:58
  • @PrzemekD That wouldn't work anyway because the / filesystem is mounted at that time. You can't overwrite a mounted fs with another.
    – Jos
    May 21, 2019 at 11:02
  • 3
    @Jos sure you can. The block level device is what the operation is performed against, not the filesystem. Unless the write utility explicitly checks to see if the block device is in use by a filesystem, the write will proceed just fine. The kernel is more than happy to let fopen() proceed.
    – phemmer
    May 21, 2019 at 13:56
  • @Melebius Xubuntu != Ubuntu. MIME type bindings can be done differently even in related distros.
    – Przemek D
    May 21, 2019 at 15:09

2 Answers 2


An ISO file is basically a disk image of an optical disk. Disk images are usually meant to be restored/extracted to a disk or partition, replacing its previous contents.

According to the size of your ISO file (3.1 GB), it might be a DVD image, so it could work when burnt to a DVD.

However, an ISO file can also be used as an archive. If you want to read files contained in an ISO file, you can mount it. This can be done using GUI or the following command:

sudo mount -o loop path/to/your/iso/file/YOUR_ISO_FILE.iso /mnt

(If you’re using /mnt for other mount(s), select another location.)

To unmount it later, issue:

sudo umount /mnt

You should also be able to browse and extract files from an ISO file using common archive managers, just like if it was a ZIP file, for example.

  • 13
    @rexkogitans Does that not imply .iso is the ISO9660 CD image file format? What else would it be? The name of the ISO9660 CD image file format? That's how you refer to file formats. MP4 is a video format. By your logic, it's not, and we should call it MPEG-4 Part 14.
    – Clonkex
    May 20, 2019 at 22:39
  • 2
    @Clonkex Just because it is a file (i.e. a named data block), it does not necessarily have a file format. You can start out to create a disk image in Linux by creating a file with dd if=/dev/zero of=file.img bs=1M size=100 and then format it with mkfs. This is a named data block, but without a specific file format. In addition, I tried to determine the file format of a Debian ISO, by using the file utility, and it said: debian-9.6.0-amd64-netinst.iso: DOS/MBR boot sector; partition ..., so also the file utility just mentions the disk partition format. May 21, 2019 at 6:11
  • @Melebius I already did +1 because this minor mistake did not affect the answer to OP's question. May 21, 2019 at 9:32
  • 2
    @Clonkex, .iso could refer to a UDF image as well. An .avi file contains a video, but the standard for it only specifies the container format, not the actual video codec used.
    – agone
    May 21, 2019 at 23:00

As @Melebius already said, ISO is a disk image format, and if you want to access the files, there is no need to restore it. Restoring to another disk will erase all the content on the chosen drive or at least destroy the drives file index.

Instead, you can simply mount the image. This is also the default action on a fresh install of Ubuntu 19.04. If it's not set as default, you should still be able to right click on the file and choose "Open with Disk Image Mounter".

open with disk image mounter

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