I know there are approximately a million variants of this question, but please hear me out!
I have a Windows 10 Pro machine, upgraded from a Windows 7 Pro pre-install; both booted in UEFI mode. I can't find confirmation I can use Boot-Repair to fix my attempt to do a dual-boot installation of Ubuntu 16.04.3 in this situation.
I believe I made the common mistake of installing Ubuntu in Legacy (BIOS) mode during an attempt to install a dual-boot. Windows 10 boots as normal, and there does not appear to be any way to boot into Ubuntu.
I know the general recommendation is to use Boot-Repair to convert Ubuntu from Legacy to UEFI boot mode. But I've done a lot of research and there are contradicting answers about whether Boot-Repair is compatible with Windows 10 machines previously upgraded from Windows 7, as opposed to Windows 10 pre-installations. Also nearly all related advice involves a different mix of Ubuntu and Windows versions.
- Will Boot-Repair work with Windows 10 upgrades from Windows 7 pre-installations, both in UEFI mode?
- How can I verify that my issue is that I installed Ubuntu in Legacy, rather than something else?
- If I can't use Boot-Repair then what should I do?
- Would it be easier to uninstall Ubuntu and start the process all over again? How would I do that?
- Bonus: Does anyone have a link to very specific, detailed instructions for doing all this? Because all the information I've found is scattered across a lot of posts and websites and/or outdated.
HARDWARE AND INSTALLATION DETAILS
- Using a Lenovo T460. Upgraded to Windows 10 (and later Creator's Update) via Microsoft's upgrade program provided online.
- Verified computer is currently booting in UEFI through Windows's System Information tool.
- Fast Startup and Secure Boot were disabled.
- Installed 16.04.3 via live-USB. Used customization option to create partition. It seemed to install as normal until I restarted the computer and tried to get into Ubuntu.
- I think the installation didn't work because I can't find any option to boot to Ubuntu, whether through interrupting the normal boot process via function keys or using Advanced Startup (accessed through Windows PC settings).
- I assume I installed in Legacy mode because I did not realize I was supposed to use UEFI until I started looking for reasons I couldn't boot to Ubuntu.
- When I go into Disk Management (see photo), I see a random 1 MB partition (red) and two partitions (purple) that add up to the size of the partition I allocated for Ubuntu. I don't know what's up with that.