I have a brand-new computer (G4560, 8 GM RAM, 2x 500 GB HDD) that I want to dual boot Windows 10 and Linux Mint. So far I have been unsuccessful.

I want to use one HDD for both OS, and the other (as NTFS) as a shared data drive.

I installed Win 10 with no issues, but am having trouble installing Mint and having the computer boot to GRUB so that I can choose which to boot to. The last point is important, since I want the computer to default via GRUB to Windows (for my wife and kids).

The problem seems to be related to the UEFI. I've turned off secure boot in the UEFI and quickboot in Win 10.

So far I've tried installing Mint as normal (25 GB / , 5 GB swap, 10 GB /home, the rest as primary), but I couldn't boot to GRUB. Afterwards, I tried installing Mint to the Windows Boot Manager partition. That worked, but for some reason got wiped the next morning. Do I need a /boot? Maybe /boot/efi? I don't even really understand what that does as opposed to regular /boot.

I use refind:
http://www.rodsbooks.com/refind/

Did you try to follow some guide, like these for example:

https://www.tecmint.com/install-linu...oot-uefi-mode/

https://duckduckgo.com/?q=installing...b=v59-3&ia=web

https://www.lifewire.com/dual-boot-w...x-mint-2202090

Those do have nice, step by step guides with pictures, suitable for newcomers. Also, in case that you are sure that you've did everything correctly and that you simply have buggy UEFI on your comp, some hints for troubleshooting you can find in these links:

https://wiki.debian.org/UEFI

https://wiki.debian.org/GrubEFIReinstall

I followed the first link you posted in my second attempt ("Afterwards, I tried installing Mint to the Windows Boot Manager partition. That worked, but for some reason got wiped the next morning.")

While it worked, as I said above, it got wiped the next day and I couldn't even find the option in the UEFI.

If it's any help, the mobo is an Asus B250M-A.

It may be an issue of me installing Mint as legacy, but I don't know how to tell.

You can't mix legacy and UEFI boot, if M$ is installed in UEFI, so does have to be Mint. Also, in that first link, you have this part:

"On computers with newer UEFI firmware the Grub boot loader won’t be displayed by default and the machine will automatically boot-up in Windows.

In order to boot into Linux you must press the special function boot key after restart and from there to further select what OS you wish to start."

Perhaps that is your case?

Do that if you really want to, but long ago I said, "to heck with that noise!"

I set up virtual machines, using VirtualBox, for any and all such purposes.

VirtualBox is free, yet it is backed by Oracle Corporation ... the "gigantic database" people. Unlike VMWare, it isn't a "hobbled horse."

With a virtual machine, you don't have to do a thing to your "host" environment in order to run other OSes. A great many of the web-sites and so-forth that you use on the Internet today run in virtual hardware.

2 members found this post helpful.

As I said in OP, it worked for a while. I even managed to install GRUB Customizer
and set up the direct-to-Windows boot, but the next morning, Mint was gone. and not just from GRUB, but from the UEFI as well. That's what got my goat.

[TUTORIAL] Installing Mint on a Windows 8/8.1/10 Computer
may offer some clues/tips/known_techniques ?

So I followed the same tecmint link step by step and everything seems to be running well. I've changed the boot order to my liking. Let's see if it lasts longer than last time.

So I followed the same tecmint link step by step and everything seems to be running well. I've changed the boot order to my liking. Let's see if it lasts longer than last time.

And the same thing happened... This morning, after my wife booted into Windows Boot Manager, my computer now quick boots to Win 10 (no GRUB), and the UEFI shows no Linux option.

Help me.

Quick boots? Did you disable fast boot option in BIOS settings?

Yes, and secure boot as well. I am out of ideas.

Up there in this thread you have links to Debian wiki and it's UEFI and GRUBEFIreinstall pages that have some hints, you also have link to refind that RadicalDreamer posted. Did you follow those links and checked any of suggestions of dealing with buggy UEFI? Specially those on Debian wiki that explain use of refind?

So, not only has Windows removed the boot option, it actually seems to have uninstalled Mint entirely!

When I use the Live USB to get into Mint, I opened gparted and saw that the root and home partitions I set up had their mount points deleted. SO that's a new wrinkle.