Grub2 Triple Boot Ubuntu Win 10 and Win 7

[mark bower]

I had a working dual boot system: Ubuntu 20.04 on a hard drive, and Win7 on another hard drive.

I have now added an additional hard drive to my PC system for a total of 3 hard drives installed, with one OS system on each: Ubuntu 20.04, Windows 10, Windows 7. A run of Grub2 does not acquire the 3rd drive, the one with Win10 (plz see image). So only Ubuntu and Win 7 remain bootable via Grub2. Both the Win7 and Win10 drives are visible in Places(Gnome classic display). All of the OS are individually bootable, though I have to manipulate boot order in the BIOS to get Win10 to boot.

I note in the boot menu in the BIOS that the Win10 drive has two entries, one with a line "Windows Boot Manager . . ." . The Win7 drive does not have a second entry. (plz see image)

What is wrong and what are options to fix the boot process? When I installed Win10, I do not recall if there were options for boot loading? May the only practical option be to reinstall Win10(a bugger compared to installing Ubuntu).

[oldfred]

Are all installs old BIOS with MBR(msdos) partitioning or all newer UEFI with gpt?
Windows 7 usually but not always was BIOS/MBR.
Microsoft has required vendors to install Windows in UEFI mode to gpt drives since 2012, but users could still use BIOS/MBR.
How you boot install media with newer systems UEFI or BIOS boot, it then how it installs.

Lets see details, use ppa version with your live installer (2nd option) or any working install, not Boot-Repair ISO:
Please copy & paste the pastebin link to the Boot-info summary report ( do not post report), do not run the auto fix till reviewed.
https://help.ubuntu.com/community/Boot-Repair &

With multiple drives, do not run any autofix in Boot-Repair. It may want to install grub to MBR of all drives if BIOS/MBR. But you want to keep Windows boot loaders for each system on its own drive. Only use Boot-Repairs advanced mode where you can choose an install and which drive's MBR to install boot loader into.
https://sourceforge.net/p/boot-repair/home/Home/

[mark bower]

thanks for reply. i saw a similar post you made but over my head, as most of your post here is, and i believe the thread was closed. i will respond tomorrow with questions and edit this post.

but for starters, i have no idea what "BIOS with MBR(msdos) partitioning or all newer UEFI" was used; i do not recall if there was a choice and/or i made a selection. i just installed and all worked as intended. unfortunately, i was not cognizant of any choice during today's install of Win 10, and frankly, was irritated the whole time with all the entries required.

[ActionParsnip]

Why Windows 7? It is no longer supported as of 14th January 2020... It's not secure and shouldn't be used by anyone for anything

[tea for one]

thanks for reply. i saw a similar post you made but over my head, as most of your post here is, and i believe the thread was closed. i will respond tomorrow with questions and edit this post.

but for starters, i have no idea what "BIOS with MBR(msdos) partitioning or all newer UEFI" was used; i do not recall if there was a choice and/or i made a selection. i just installed and all worked as intended. unfortunately, i was not cognizant of any choice during today's install of Win 10, and frankly, was irritated the whole time with all the entries required.

UEFI with GPT is superior to BIOS with MBR

Are you familiar with your UEFI set up screens (accessed by a dedicated keystroke at Power On) because that is where you control the boot mode (UEFI or Legacy and/or mixed)?

If you have mixed boot mode set up, then you control the mode with the PC boot menu.
UEFI:Kingston or other device name will indicate that the live session will boot and eventually install in UEFI mode.

Each disk with a separate OS is perfect but please heed the comment by ActionParsnip and remove Windows 7.

Anyway, please post the boot-repair report as requested by oldfred and I'm sure that you will receive good advice/recommendations.

[tea for one]

Why do you have old kernels (4.4.0-97) in the thumbnail of your first post?

The current kernel for Ubuntu 20.04 is 5.4.0-58.

[yancek]

Based on the information in your initial post it is almost certain that you have windows 7 installed in what is referred to as Legacy/CSM mode and Ubuntu the same. A windows 7 default install will be Legacy which is a boot system that predates the existence of windows (1970's). A default install of windows 10 on a GPT drive will be UEFI. If this is the way the systems were installed (boot repair will tell us that) you will be unable to boot windows 10 installed UEFI from a Legacy install of any Linux Grub installed in Legacy mode. I don't beleive a UEFI install of Linux Grub will boot a Legacy install of windows.

I don't have the unsupported windows 7 installed but I am pretty certain windows 7 bootloader will not boot a UEFI install of windows 10, nor will a windows 10 UEFI boot a Legacy windows 7.

The link below to the Ubuntu documentation gives detailed information on UEFI and mixing modes and its problems (Legacy/UEFI).

https://help.ubuntu.com/community/UEFI

[oldfred]

From the link in my signature below.

Acronyms:
UEFI https://wiki.archlinux.org/index.php...ware_Interface
ESP/efi - Efi System Partition http://en.wikipedia.org/wiki/EFI_System_partition
https://en.wikipedia.org/wiki/BIOS_boot_partition
BIOS - Basic Input/Output System http://en.wikipedia.org/wiki/BIOS
CSM - UEFI Compatibility Support Module (CSM), which emulates a BIOS mode, only available with secure boot off.
grub2 https://wiki.archlinux.org/index.php/GRUB2
gpt(GUID) http://en.wikipedia.org/wiki/GUID_Partition_Table
MBR(msdos) http://en.wikipedia.org/wiki/Master_boot_record

[mark bower]

I spent almost two hours preparing a detailed response on my discoveries, how I did it, and addressed everyones' posts, then somehow deleted the post!!!!! So now a very cryptic response - sorry.

Disk 1 Ubuntu = Legacy Boot on HHD
Disk 2 Win7 = BIOS
Disk 3 = EFI.

So I have a mix. I tried messing with the BIOS settings and CSM in particular, but did not effect a change in boot behavior. I attached screen shots to show CSM settings, and not reflected, I tried OS Type set to "Other", but again, no effect.

So can the problem with Win10 being a UEFI boot loader vs legacy be fixed in the BIOS settings, I gather not? If not, can I just do a clean install of Win10 again, but pay heed to a possible initial setup choice of setting to Legacy BIOS?

Two side comments: The Ubuntu OS is 16.04, not 20.04 as I stated. And I run ACAD2000 and TaxAct on Win7 32bit. With Win10, I will probably use TaxAct and an app that is only offered in 64bit.

[tea for one]

The solution here is now more apparent.

Leave Windows 10 in UEFI mode and install your TaxAct software.
Double check that everything works OK.

Ubuntu 16.04 reaches End of Life in April 2021.
Back up data and install Ubuntu 20.04 in UEFI mode.
Run sudo update-grub to pick up Windows 10 bootloader. (I would not do this because it's no problem to use the PC boot menu rather than grub)

Remove Windows 7 completely as it is unsupported.

Separate disks for each OS is highly desirable.
If you can, remove, de-activate or isolate your Windows 10 disk when installing Ubuntu 20.04 to eliminate any human error.
Always have backups ready.