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I was installing 32-bit Ubuntu(ubuntu-10.10-desktop-i386.iso) on VMWare workstation 7.1. During installation an error came up with the following text.

(initramfs) mount: mounting dev/loop0 on //filesystem.squashfs failed: Input/Output error Can not mount /dev/loop0 (/cdrom/casper/filesystem.squashfs) on //filesystem.squashfs

I did a memory test which was successful, but when selecting "Try Ubuntu without installing", "Install Ubuntu" or "Check disk for defects" the same error is showing up.

I download the ISO image from Ubuntu website "http://www.ubuntu.com/desktop/get-ubuntu/download". As I couldn't find the checksum data, the ISO image was verified by mounting to a virtual drive and browsing the contents.

The ISO image is mounted to a virtual drive in VMWare and not burnt to a CD.

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It looks like a corrupt image. Anyway, what is your guest OS?. –  Javier Rivera Oct 11 '10 at 16:13
I have the same problem but on my machine i dont have an operatiing system how can i install ubuntu? really frustrating i cant get the windowsa working on my machine nor i cant get the ubuntu installed –  user10327 Feb 6 '11 at 21:50

3 Answers 3

up vote 4 down vote accepted

The checksums (MD5) can be found on releases.ubuntu.com. I would suggest you do the following:

  1. Check that the MD5 checksum of the ISO image you downloaded matches the one in the aforementioned link, by following these directions.
  2. If that looks okay, boot the CD and press the Spacebar key when you see the keyboard icon in the bottom-center of the screen. Select your language, then the "Check CD for defects" boot option.

If neither of those produce any errors, please file a bug here, following these instructions to attach /casper.log to it.

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on the cd I created today there is no "Check CD for defects", there is "Check disc for defects" though -- leaving me with the question does that refer to cd or hard drive? In any case when I pick it I get the same failure message as in the question. –  matt wilkie Oct 27 '10 at 19:55
...and after checking md5sum discovered the iso was bad. Thanks for the good answer. –  matt wilkie Oct 27 '10 at 20:05

There are two common culprits of this error:

  1. the CD or disk you burnt to did not have enough space for the entire .iso
  2. the .iso you downloaded had a problem when downloading

Make sure you at least do these simple checks when going to install:

  1. check that the size of the downloaded .iso isn't ridiculous (Ubuntu 10.x and 11.04 are each approximately 680mb, if you're is only like 400, you obviously have a problem)
  2. check the amount of free space on your CD or disk before you burn to it (and remember, DVDs have lots more space than a generic CD)
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Did you check the download prior to burning?

You can use a program such as winMD5Sum in Windows to check md5sums

enter image description here


The hashes you need to check against the downloaded iso can be found here https://help.ubuntu.com/community/UbuntuHashes

If you downloaded with a torrent then it should be checked as it downloads though.

If the hash check is ok then reboot with the cd and check it's integrity.

Press any key as the cd loads to see the cd menu

enter image description here

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