Since you cannot boot windows 8.1 from BIOS, you may have a different problem.
However, I do notice that many people are unable to dual boot window 8.1 and Ubuntu in UEFI Secure Boot mode: http://ubuntuforums.org/showthread.php?t=2187907 I have this same problem, I cannot boot Windows 8.1 from grub, but I can boot it from BIOS menu. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1308758 Title: Ubuntu 14.04 install blocks Windows 8.1 from booting in dual boot To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1308758/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
