Existing partitons not recognized during installation

Question

I've got a Windows 8 (final version, no preview) installed in my pc. Now I wanted to install Ubuntu like I've done a thousand times before. Strange thing is, gparted (started from live USB-Stick) sees my system disk as completely unallocated although it has one huge ntfs partition with Windows 8 on it. So I booted into Windows again and used the disk management tool to shrink that partition and create a new one in the free space. I formated that one to fat32. I still got the same behavior in gparted. Does anyone have an idea? My harddisk is a Samsung 830 Series SSD and the mainboard has UEFI.

EDIT

Tried a 12.10 beta1 stick now. It tells me that the volume contains GPT signatures and maybe was corrupted by a program that doesn't understand. With this new information I found this but am not really sure what to do.

Answer 1

I found the solution here. The basic part is:

OK, then, it looks like you've got a new MBR with residual GPT data, which is confusing GParted. You'll have to wipe the GPT data. Here's how:

Boot your PartedMagic or System Rescue CD emergency disc.
For safety, back up your MBR by typing "dd if=/dev/sda of=sda-backup.mbr bs=512 count=1" and then copying the resulting file (sda-backup.mbr) to a USB flash drive, network share, or some other medium. Be sure to get the if= and of= parameters right, though!
Launch gdisk by typing "gdisk /dev/sda". When asked whether to use the MBR or GPT data, either will work.
Type "x" to enter the experts' menu. The command prompt should change.
Type "z" to "zap" (destroy) the GPT data. Tell it to proceed, but answer "N" to the question about blanking the MBR.

That's it. Windows should boot as it did before and you should now be able to continue your installation of Ubuntu; its installer should now see the same partitions as Windows.