[ubuntu] Installer not seeing partitions, ? overlapping partitions

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http://ubuntuforums.org – I am trying to install Ubuntu in AMD 64 machine with Windows 7 and Windows 8 Developer Preview installed. Neither the installer or GPARTED sees any partition. However I have access to all windows and data partitions from live desktop. Removing dmraid did not work. Using Fixparts also did not correct the issue. Below is the report from sfdisk: ubuntu@ubuntu:~$ sudo sfdisk -uS -l /dev/sda Disk /dev/sda: 91201 cylinders, 255 heads, 63 sectors/track Warning: extended partition does not start at a cylinder boundary. DOS and Linux will interpret the contents differently. Units = sectors of 512 b (Hardware)