With a UEFI Win8 machine, you usually *don't* have an MBR. By installing an
MBR (win or grub) on it, you've possibly ruined your GPT partition table.
When installing a UEFI-capable Linux distro, you use/mount the Win8 /uefi
partition as your /boot partition in Linux. Obviously, you do NOT allow
it to be partitioned.
The following is a bit dated now, I kept it for my own assistance in case
I needed to do it again, but it's how I did it about 12 months
back on an Acer XC-100. This may be of assistance to you (and/or others),
possibly not. YMMV:
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It seems it's better installing Mint dual-boot on a newer UEFI Windows 8
machine is by ensuring that the Mint 14 install medium boots ONLY in EFI
mode. I couldn't do that using a DVD drive, as it always insisted on
booting in the old BIOS. Use unetbootin to make a fresh USB key with the
contents of the Mint 14.1 DVD iso-image. Ensure there is an EFI
subdirectory.
Start to boot up Windows8, but hit the DEL key when the Acer logo shows and
a beep is heard (if you're not using an Acer, check what key is needed for
your brand of computer) to reach the BIOS configuration screen. Go to the
Authentication screen, and turn off Secure-Boot. Then proceed to the
Boot-Options screen and turn on CSM so that we can boot using the normal MBR
type of boot-system. On the same screen (on Acer) check the order of boot
devices, we want to give USB keys and/or CD/DVD devices priority over the
hard drive. Also ensure that the boot-menu is enabled, otherwise you won't
be able to select the USB key to boot from and therefore you won't be able
to boot into anything else but Windows. Save and exit.
When you've opened Windows, shrink the C: drive by opening Control-Panel ->
System and Security -> Administrative Tools -> Computer Management ->
Storage -> Disk Management. Right-click on the C: drive and select Shrink
Volume. Adjust the shrinkage to suit yourself. If you have a D: drive,
then shrink that at the same time if you want.
[Handy Hint: Because of the way the original hard-drives are produced and
supplied in your OEM machine, it is usually very hard to shrink the C: drive
very much using the Control Panel method on your OEM untouched hard-drive.
But when you use the complete recovery method from your Windows Recovery
Disks which you made after you began using your Windows machine, files are
not scattered all over the partition, but are all compacted better and you
will usually be able to condense the C: partition very easily. So delete
your C: partition (if you're brave enough <grin>) and use your Windows
Recovery Disks to get back to a Factory-Defaults install of the machine. If
you're even braver, you can adjust the Recovery Disk files to partition the
Windows partitions to your desired sizes on recovery.]
At this point I use Gparted Live CD and an external USB hard-drive to
back-up all those Windows partitions as belt-and-braces. You should already
have made your Windows Recovery System disks anyway. These were my original
hard-drive partitions, notice that on a GPT partition system *all*
partitions are *primary* partitions.
original clean Windows 8:
Partition Table: gpt
Number Start End Size File system Name Flags
1 1049kB 420MB 419MB ntfs Basic data partition hidden, diag
2 420MB 735MB 315MB fat32 EFI system partition boot
3 735MB 869MB 134MB Microsoft reserved msftres
4 869MB 492GB 491GB ntfs Basic data partition
5 492GB 985GB 492GB ntfs Basic data partition
6 985GB 1000GB 15.6GB ntfs Basic data partition hidden, diag
I then set up my hard-drive so that I like it:
Partition Table: gpt
Number Start End Size File system Name Flags
1 1049kB 420MB 419MB ntfs Basic data partition hidden, diag
2 420MB 735MB 315MB fat32 EFI system partition boot
3 735MB 869MB 134MB Microsoft reserved msftres
4 869MB 52.0GB 51.1GB ntfs Basic data partition
5 52.0GB 78.2GB 26.2GB ntfs
6 78.2GB 94.0GB 15.7GB ntfs hidden, diag
7 94.0GB 105GB 10.7GB ext4
8 105GB 115GB 10.7GB ext4
9 115GB 118GB 2097MB linux-swap(v1)
10 118GB 149GB 31.5GB ext4
11 149GB 1000GB 851GB ext4
Fast Summary:
Shrink C: partition to your taste. I cut mine back all the way to just
50Gig. I kept a very small D: partition just as a place-keeper to keep all
the Windows partitions in the same relative positions. I sometimes move
/dev/sda6, but I feel it's easier and simpler to just delete the original D:
(/dev/sda5) and 'One Touch Reset' (/dev/sda6) partitions and make new ones,
restoring the contents of the 'One Touch Reset' partition from the backups.
Then make all your Linux partitions: *two* root partitions in case I want to
experiment with another distro, swap of course, a separate /home so I can
just carry over everything to a new distro if required (not too big a /home
directory, it's just for day-to-day work), then a large separate storage
partition for long-term files/archives.
Then proceed to the Boot-Options screen and turn CSM off again so that we
can't boot using the normal MBR type of boot-system. On the same screen (on
Acer) confirm that the boot-menu is enabled, otherwise you won't be able to
boot into anything else but Windows.
Save and exit. The machine will now reboot using EFI *only* and restricts
you to only booting up Windows and other EFI systems.
At the Acer logo and beep, hit the F12 key, a boot-menu will display. Move
the bar to the entry for the USB key with Mint 14 and which is marked 'UEFI'
and select.
Install normally. When you get to the 'Installation Type' page, select
'something else'. Use the 'Change' button to select your intended
partitions as the root, /home and other mount points for your filesystems.
Be careful not to touch any of the Windows 8 partitions. Leave the 'sda'
entry as the position for the grub boot device. Then click on 'Install Now'
With my install, grub would install to the UEFI boot, but would find only
Mint, so I was unable to boot Windows. Fixing the boot-up is the purpose of
'boot-repair'. So I downloaded the boot-repair package(s) with these
commands:
# sudo add-apt-repository ppa:yannubuntu/boot-repair && sudo apt-get update
# sudo apt-get install -y boot-repair && boot-repair
boot-repair will scan for a while. Accept the 'Recommended Repair'.
And that's it. Now you have a dual-boot Windows 8 and Mint 14.1 system
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Hope this helps you in some way.
Regards.