I booted windows 10 and ubuntu 16.04 uefi before trying to I stall 18.04. I did NOT receive any such warning whatsoever when trying to I stall 18.04.. Don't know where you got that idea.
I tried custom partitioning and creating an efi partition but 18.04 simply will not install grub. I booted 16.04 uefi and re-installed 16.04 with no issue before forcing an upgrade to 18.04 in apt. System is now booting uefi 18.04 and win10 only due to the work around of forcing the upgrade. The 18.04 media will NOT install whereas 16.04 will. Based on that alone, there is obviously something different happening in the 18.04 package. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1767703 Title: Calling 'apt-install grub-efi-amd64-signed' failed To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub-installer/+bug/1767703/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs