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I see the following messages from both primary and alternate Ubuntu and Kubuntu Live Cds.

error: "prefix" is not set. 


booting a command list
you need to load a kernel first

Both these messages are displayed very early in the boot process, the first just after the boot begins and the second immediately after I select from the "Try or install" menu.

Selecting any option from "Try or install" leaves the system locked that needs a hard reboot.

I always see this on Live Cd's of Ubuntu/Kubuntu 12.04. But never on a Live USB.

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up vote 0 down vote accepted

You say 'burnt onto a CD'. It should be on a DVD as it is oversized. Brasero would tell you that. If you used a buggy CD burner it might have burned you a buggy CD. This is why you are not getting the problem with a USB stick.

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I should have noticed that. However, I have to say that the ISO images are showing as just under 700 MB on the mirrors and while they are downloading, but they're coming in at 730+ MB on my drive. – jonc May 7 '12 at 21:59
@jonc This sounds like the classic albeit ever annoying MiB versus MB confusion. 700 MiB is essentially 734 MB. For a related commentary on this from someone associated with Stack Exchange, there is this: Gigabyte: Decimal vs. Binary – irrational John May 12 '12 at 17:39

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