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I just got a new 240 gig SSD for my laptop. I installed Windows 8.1, partitioning off half of it for Windows and leaving the rest reserved for Linux. Everything works great. Then I installed Ubuntu 14.04 LTS. Windows created its primary partition and a couple recovery partitions, all in NTFS. I had Ubuntu create a 6 gig swap file partition and use the remaining space for an ext4 primary partition.

Right now I'm running into the issue where grub will come up when I'm booting, and I have options for Ubuntu and Windows 8.1, but when I go to Windows I get the error: Trouble dual-booting Win8.1 and Ubuntu, "error: disk 'sda6,gpt1' not found"

sda6 is the partition that Windows is installed on, according to Ubuntu. Below I've attached the contents of the file /etc/grub.d/40_custom. Please let me know what else you may need to help.

exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
    menuentry "Windows 8.1" {
    set root='(sda6,gpt1)'
    chainloader /EFI/microsoft/BOOT/bootmgfw.efi


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I have following lines for Windows boot manager: (in \boot\grub\grub.cfg)

menuentry 'Windows Boot Manager (on /dev/sda2)' --class windows --class os $menuentry_id_option 'osprober-efi-92A2-051C' {
    insmod part_gpt
    insmod fat
    set root='hd0,gpt2'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt2 --hint-efi=hd0,gpt2 --hint-baremetal=ahci0,gpt2  92A2-051C
      search --no-floppy --fs-uuid --set=root 92A2-051C
    chainloader /EFI/Microsoft/Boot/bootmgfw.efi
set timeout_style=menu
if [ "${timeout}" = 0 ]; then
  set timeout=10

where 92A2-051C is Volume ID of EFI System partition on /dev/sda.

sudo update-grub2 should regenerate your grub.cfg.

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