amd64 debian-installer, natty from 04/05 fails

This also happens exactly when trying to install it on an Intel Mobo (DG33BU)

broken on the final ubuntu-11.04-desktop-amd64.iso too on the Samsung R530 laptop

same behavior on the -amd64+mac.iso too, which handles efi boot differently

Same thing happens on my macbookpro 8,1. I tried installing via USB, no changes. But when I install in a virtual machine, all goes well.

I tested on Kubuntu 64bit desktop CD.

Also happens on LG P210 with Ubuntu 11.04 amd64

Enabling Legacy OS boot option from the BIOS solved the problem. Now I can start the computer with live ubuntu 11.04 over a USB.

It also happens on my CCE (a Brazilian computer maker) laptop with an Intel i7-2630QM sandy bridge processor. I'm not sure about the maker of the motherboard. I searched the BIOS options but found no Legacy OS as memedemin said earlier.

I'm running Ubuntu 10.04 64x and I just tried 11.04 32bits and it worked - but I do not intend to keep a 32bit OS.

This was not a problem till I recently updated my ubuntu linux kernel. when i boot into ubuntu it took a long time saying something about checking the disk or something.

After that trying to boot ubuntu always ends up with a black screen and going into recovery mode tells me that my /home is not ready or cannot be found. going into gpart tells me that it has indeed become an unallocated partition.

my attempts at booting using ubuntu cd is met with the same problems as described in this thread. I first see Error: Prefix not set then a menu of 3 comes up and they all end up with a black screen with only an underscore on the screen and it doesn't help to wait

Experienced the same problem on a Fujitsu LIFEBOOK P771. Adding "noefi" to the kernel command line (which instructs the kernel not to access the UEFI Runtime Services) allowed me to boot into the live system.

I confirm Daniel's workaround allowed me to boot the 64x version of Ubuntu's 11.04 and had no problems on installing the Operating System afterwards. Thanks a lot!

HI hopugop and Daniel . Can you please describe in detail the whole process? I still did not solve the problem, thanks.

ychleo, on the Ubuntu CD/USB bootscreen where you can select Install System, Check RAM, Boot from First Hard Drive etc just highlight Install System and press E to Edit the boot command line. Add NOEFI to the end of the first line (just move the cursor to that point and type in) then hit Enter (or any other key indicated in the dialog) to proceed with booting. Works for me!