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I am trying to install Ubuntu 12.10 64b on dual-boot with preinstalled W8.

I already burnt a bootable USB with ubuntu-12.10-desktop-amd64 and configured my BIOS (EFI, secure boot disabled) to boot from there.

I can boot from USB and test Ubuntu from the pendrive but Gparted shows the following error:

backup GPT table not at the end of the disk. This might mean that another OS believes disk is smaller . Fix by removing the bakcup to the end (and removing the old backup)

showing "fix", "cancel" and "ignore" as options.

I am unaware how to proceed in order to avoid messing things up with W8.

I also tried to install Ubuntu through Wubi which did not work either (but that is another help topic...)

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up vote 1 down vote accepted

Is the error in reference to your hard disk or to your USB flash drive? If the latter, just ignore the error and proceed with the installation; it's not really important. If it's in reference to the hard disk, though, there are two possibilities:

  • Your disk may be damaged, in which case using the "fix" option is likely to do as the name implies; however, I can't be sure without seeing more details. If you want more advice, try running gdisk, typing p and v from its main menu, and posting the results here. (You'll need to either install gdisk manually or run it from an emergency system like Parted Magic or System Rescue CD.)
  • You may be running into inconsistencies because the disk was prepared with motherboard-based software RAID (aka "fake RAID" and various other names) enabled and Linux isn't using that feature, or possibly vice-versa. If this is the case, you'll need to decide whether or not you want to use that type of RAID and set up all your OSes and your firmware to treat the disk consistently. The details depend on how you want to proceed. Once this is set up consistently, either parted will stop complaining or you can use the "fix" option to fix the inconsistency.

The second possibility is more likely, particularly on a new computer. There are many forum posts and Web articles about this type of problem, but I don't happen to have any URLs handy.

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Hi Rod, thank you for your prompt answer. As a matter of fact, I cannot run gparted from a SRCD, I keep getting a "gpartedbin GTK-warning: cant open display" error msg when I want to open gparted from command line. W8 shows me two different devices, Disk0 with two recovery partitions, an EFI system partition and one NTFS with boot, pagefile, crash dump, primary partition, whereas Disk1 only shows as primary partition. – Jose May 13 '13 at 22:21
Running gparted in graphis mode starts firing all kind of error msgs regarding GPT table corruptness, very similars to the ones gotten when booted from Ubuntu usb – Jose May 13 '13 at 22:27
Unfortunately, "all kind of error messages" is insufficient detail. When dealing with technical problems, it's critical that you report the precise error messages. Also, as I recommended originally, gdisk's v option will provide useful diagnostic information on your GPT data structures. – Rod Smith May 14 '13 at 15:48
Apologies for my ignorance, succesfully ran gdisk and found 3 devices, two of them gave the following error upon selecting "v" option: Secondary header's self-marker indicates that it doesn't reside at the end of disk. If you've added a disk to a RAID array, use the 'e' option at the experts menu to adjust secondary's header and partition table's locations – Jose May 14 '13 at 17:00
My suspicion is that you're running into the RAID inconsistency I noted in my initial response. How to proceed depends on several factors, though, such as whether you're actually using RAID and what sorts of settings your firmware has for RAID. It's also entirely possible that the problem has a fundamentally different cause. Basically, your problem is very system-specific, and you need more interactive help than this site is designed to offer. You may be better off asking at Ubuntu forums. – Rod Smith May 14 '13 at 23:12

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