I decided it was time to update my ubuntu (single boot) computer from 64-bit v10.04 to 64-bit v12.04. Unfortunately, for some reason (or reasons) I just can't make it work.

Note that I am attempting a fresh install of 64-bit v12.04 onto a new 3TB hard disk, not an upgrade of the 1TB hard disk that has contained my 64-bit v10.04 installation. To perform the attempted install of v12.04 I unplug the SATA cable from the 1TB drive and plug it into the 3TB drive (to avoid risking damage to my working v10.04 installation).

I downloaded the ubuntu 64-bit v12.04 install DVD ISO file (~1.6 GB) from the ubuntu releases webpage and burned it onto a DVD. I have downloaded the DVD ISO file 3 times and burned 3 of these installation DVDs (twice with v10.04 and once with my winxp64 system), but none of them work. I run the "check disk" on the DVDs at the beginning of the installation process to assure the DVD is valid.

I also tried to install on two older 250GB seagate drives in the same computer. During every attempt I plug the same SATA cable (sda) into only one disk drive (the 3TB or one of the 250GB drives) and leave the other disk drives unconnected (for simplicity).

Installation takes about 30 minutes on the 250GB drives, and about 60 minutes on the 3TB drive - not sure why.

When I install on the 250GB drives, the install process finishes, the computer reboots (after the install DVD is removed), but I get a grub error 15.

It is my understanding that 64-bit ubuntu (and 64-bit linux in general) has no problem with 3TB disk drives. In the BIOS I have tried having EFI set to "enabled" and "auto" with no apparent difference (no success).

I have tried partitioning the drive in a few ways to see if that makes a difference, but so far it has not mattered. Typically I manually create partitions something like this:

8GB swap 8GB /boot ext4 3TB / ext4

But I've also tried the following, just in case it matters:

100MB boot efi 8GB swap 8GB /boot ext4 3TB / ext4

Note: In the partition dialog I specify bootup on the same drive I am partitioning and installing ubuntu v12.04 onto. It is a VERY DANGEROUS FACT that the default for this always comes up with the wrong drive (some other drive, generally the external drive). Unless I'm stupid or misunderstanding something, this is very wrong and very dangerous default behavior.

Note: If I connect the SATA cable to the 1TB drive that has been my ubuntu 64-bit v10.04 system drive for the past 2 years, it boots up and runs fine.

I guess there must be a log file somewhere, and maybe it gives some hints as to what the problem is. I should be able to boot off the 1TB drive with the 3TB drive connected as a secondary (non-boot) drive and get the log file, assuming there is one and someone tells me the name (and where to find it if the name is very generic).

After installation on the 3TB drive completes and the system reboots, the following prints out on a black screen:

Loading Operating System ... Boot from CD/DVD : Boot from CD/DVD : error: unknown filesystem grub rescue>

Note: I have two DVD burners in the system, hence the duplicate line above.

The same install and reboot on the 250GB drives generates "grub error 15".

Sigh. Any ideas?

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motherboard == gigabyte 990FXA-UD7 CPU == AMD FX-8150 8-core bulldozer @ 3.6 GHz RAM == 8GB of DDR3 in 2 sticks (matched pair) HDD == seagate 3TB SATA3 @ 7200 rpm (new install 64-bit v12.04) HDD == seagate 1TB SATA3 @ 7200 rpm (current install 64-bit v10.04) GPU == nvidia GTX-285 ??? == no overclocking or other funky business USB == external seagate 2TB HDD for making backups DVD == one bluray burner (SATA) DVD == one DVD burner (SATA)

The current ubuntu 64-bit v10.04 system boots and runs fine on a seagate 1TB.