The same issue. Ubuntu broke my Windows EFI system partition, installing Ubuntu EFI on it, despìte I have told Ubuntu to use the external drive.
*To fix the Windows EFI system partition:* * Boot on Windows CMD using a Recovery Partition/USB Drive ** Windows Bootloader Recovery -> System Restore – > Troubleshoot-> Command Prompt diskpart list disk list partition list volume sel disk 0 (Select the disk with the Windows EFI system partition) Assign the drive letter K: to the hidden EFI volume: select volume 1 (select the volument with the Windows EFI system partition) assign letter K: exit cd /d K:\efi\microsoft\boot\ attrib BCD -s -h -r ren BCD BCD.bak bcdboot C:\Windows /l en-us /s k: /f ALL *Don't use this commands, because this are only for MBR not UEFI mode:* * bootrec /fixboot * bootrec /scanos * bootrec /rebuildbcd * or even: * bootrec /FixMbr -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1396379 Title: installer uses first EFI system partition found even when directed otherwise To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1396379/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs