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I'm trying out VirtualBox 4.18 and wanted to install Ubuntu 12 as a test. After installing VirtualBox (on Debian squeeze/sid), creating a virtual machine for Ubuntu and pointing it in Settings > Storage > IDE Controllers to the ISO with the proper version of Ubuntu, checked the "Live CD" option. Tried to define the IDE as master / slave, primary / secondary - all to no effect, and trying to boot this system, I'm getting to the screen which says:

FATAL: could not read from the boot medium! System halted

I've copied the same ISO to the USB stick, and I can boot from the USB (outside VirtualBox).

I've looked at couple of tutorials / walk-through, there's nothing I can see that I would've done wrong.

So, how would I configure it to boot from the desired ISO?

Below is the snapshot with the current settings (sorry, I don't know how to get them as text).

enter image description here

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Have you checked, if MD5 hash of the image is correct? – krnekit Aug 15 '12 at 20:07
Bah... it's actually wrong. OK, I'll redownload and will see in a few minutes. – wvxvw Aug 15 '12 at 20:16
Actually... this appears to be a bug on Ubuntu's download site... they serve the wrong version, if you select it by clicking the button rather than by finding the correct URL for download. Ubuntu is soon to be more Windows then Windows :/ Just spent an hour waiting for the wrong version to download. – wvxvw Aug 15 '12 at 21:34
@krnekit you can make your comment into an answer. That was it. – wvxvw Aug 16 '12 at 6:19
up vote 1 down vote accepted

When you download ISO images, at first check MD5 checksum. It is usually can be found in the file named MD5SUMS or IMAGE_FILE.md5 on the site you download from. Use the following command to get MD5 checksum on Linux:

$ md5sum IMAGE_FILE

If checksums does not match - your image is broken and you need to redownload it.

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I had the exact same symptom with a different resolution.

VirtualBox (running with Windows 7 64-bit host) automatically added the physical CD/DVD drive. I added an additional CD/DVD drive mapped to the Ubuntu installation ISO. When attempting to boot, apparently VirtualBox only recognized the physical CD/DVD drive.

I simply removed the physical CD/DVD drive and suddenly my ISO was seen.

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