"errno 5 - input/output error" when trying to install Ubuntu

I had this problem too, during installation...

[Errno 5] Input/output error

Target machine was a brand new Asus K53e laptop. Installation image was ubuntu-11.10-desktop-amd64.iso (64-bit). I burned this image to CD... Errno 5. Burned it to bootable USB stick... Errno 5 again :( I tried 4 or 5 times.

fsck said the entire root partition was fine (after 10 hours). memtest86+ said all 6GB of RAM was fine too. I tried installing directly when the live image booted up (Install Ubuntu). I also tried the Try Ubuntu button, then ran install from the live desktop. Again, Errno 5.

In the end, it turns out the iso file I downloaded was somehow out of date or wrong. Can you believe it!?

$ md5sum ubuntu-11.10-desktop-amd64.iso

The output was different from Ubuntu's official hash (62fb5d750c30a27a26d01c5f3d8df459). Then I cast my mind back. I remember, when I downloaded this image, I think I was forwarded from ubuntu.com to a mirror site, and I chose a French one at random because my nearest UK mirror was down. It must've been slightly out of date or something. In fact, I now remember seeing entries like this

SQUASHFS error: zlib inflate error, data probably corrupt
squashfs_read_data failed to read block 0x1e457bbd

in the output of dmesg (I think) or somewhere in /var/log when checking after the installation crash dumped me back to the live (Try Ubuntu) desktop.

Basically, make sure you check the MD5 hash of your downloaded ISO file! (I know. I know. I rarely check either!)

Anyway,I downloaded 64-bit Ubuntu 11.10 again and, this time, I was prompted with a Save As dialog, instead of being asked to choose a mirror site. When downloaded, checksum matched :) Installation ok :)

You may have some bad sectors on the target HDD.

To check sda1 volume for bad sectors in Linux run fsck -c /dev/sda1. For drive C: in Windows it should be chkdsk c: /f /r.

IMHO chkdsk way will be more suitable as it will remap bad blocks on the HDD while Linux fsck simply marks such blocks as unusable in the current file system.

Quote from man fsck.ext2

-c This option causes e2fsck to use badblocks(8) program to do a read-only scan of the device in order to find any bad blocks. If any bad blocks are found, they are added to the bad block inode to prevent them from being allocated to a file or directory. If this option is specified twice, then the bad block scan will be done using a non-destructive read-write test

This could be the result of bad RAM in your computer. I had a similar problem and it turned out to be that. Try testing your RAM by booting from the USB flash drive and, as soon as you see the keyboard and person icons at the bottom of the screen, press a key to show the non-graphical boot menu. Then select the option to test your RAM, from there.

If that reveals a defect in your RAM, then you'll have to remove or replace the affected RAM stick. (If you don't feel comfortable with doing this, you should enlist the assistance of a friend, professional, or other acquaintance with hardware experience. Since this would be a hardware issue, you could ask on Super User for advice about it, too.)

This could also be the following problems:

• Bad installation media (either physically defective, or, more likely, a corrupted write or corrupted ISO image). MD5SUM the Ubuntu ISO you used to make sure it's good (and if it's not, download a new one, MD5SUM it too, and start over with it).

  Also verify that the USB drive was written correctly by selecting Check disc for defects from the same menu that has the RAM test option (see also this video).

• There could be a problem with the drive you're trying to install Ubuntu to. If you have another drive, you could try installing it to that. Since the live system (running off the flash drive itself) works, you could test your hard disk with smartctl as explained in the Failing Disk section of this article.