Yes, I meant that I installed natty on sda8 via live-usb stick and it is a ext4 partition.
here is the output of "sudo os-prober": /dev/sda3:Windows Recovery Environment (loader):Windows:chain /dev/sda8:MS-DOS 5.x/6.x/Win3.1:MS-DOS:chain and here of "sudo sfdisk -l /dev/sda" Disk /dev/sda: 60801 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 = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End #cyls #blocks Id System /dev/sda1 0 - 0 0 0 Empty /dev/sda2 0+ 58675- 58676- 471313409 5 Extended /dev/sda3 58676+ 60788- 2112- 16963584 17 Hidden HPFS/NTFS /dev/sda4 60788+ 60801- 14- 105496 1c Hidden W95 FAT32 (LBA) /dev/sda5 7594+ 56717- 49124- 394585937+ b W95 FAT32 /dev/sda6 1867+ 2365- 498- 3998720 82 Linux swap / Solaris /dev/sda7 2365+ 7594- 5229- 41999360 83 Linux /dev/sda8 0+ 1867- 1868- 14998528 83 Linux /dev/sda9 * 56717+ 58675- 1958- 15727616 83 Linux Thanks! -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/791707 Title: New Version of grub in oneric (11.10) is unable to find natty (11.04) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/os-prober/+bug/791707/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs