GRUB bootloader doesn't show Windows 7

Mojtaba Mokhtari

12/22/23, 5:41 PM

I have installed Windows 10 alongside Windows 7 and Ubuntu, but GRUB only shows Windows 10 and Ubuntu in its screen. If I want booty Windows 7 I have to choose Windows 10 and in the Windows bootloader I can choose Windows 7, but I want both Windows OSs to show up in the GRUB screen.

GRUB screen:

Windows bootloader:

220

1 + 2

boot

grub2

dual-boot

windows-7

Joepie Es

12/22/23, 9:24 PM

What version of Ubuntu and Grub2 are you running? I asume that OS-prober is enabled (see Etc/grub ), or did you manually added Win10 to the menu?

oldfred

12/22/23, 9:40 PM

Windows uses its Boot-Repair to know where to boot in BIOS mode. Only one boot partition per drive. So Windows moves boot files from one install and adds entry to BCD. Then grub cannot find boot files from first install. If only booting from grub, you can move boot flag, repair Windows, so both have boot files. Move boot flag back. And grub will be able to directly boot both. All Windows installs must be in primary partitions or you cannot do the repair.

Score:0

Ubuntu

sean

12/23/23, 8:14 AM

Your problem here is:

Windows 7 doesn't support EFI and boots off MBR partitions, it doesn't understand GPT partitions at all. Windows 10 understands GPT partitions and will boot through UEFI, as will Ubuntu. Which means to run all this together you have to run everything in a degraded MBR format partition which support for is dying day by day.

So, the short of it is... You are getting trouble because Windows 7 is an EOL turd that doesn't boot the way that things have done for the last 10 years. Next, up...

Because of this configuration you have to load things in a particular order... You have to load Windows 7, then Windows 10, then Ubuntu. You then have to configure grub to chain load the Windows versions. If you do it any other way then your system gets loaded UEFI and then the Windows 7 boot gets wiped or Windows 7 won't install without damaging the partitions for the other OS. (Both Windows 10 and Ubuntu will default to loading GPT partitions and UEFI, but both will switch to MBR if that is what is present on the installation drive before they get there.)

But, let's get back to the tacks... There is legitimately zero reason to run Windows 7 at all in this configuration - 10 is backwards compatible with Windows 7. It will even run Windows 7 drivers, it's completely redundant. I would not recommend running ANY EOL unsupported commercial OS on your computer. It's not secure, safe, nor are bugs being fixed anymore.

Windows 11 is UEFI ONLY, so if you're thinking, "Oh, I'm going to load that..." Essentially, Windows 11 is EOL for MBR... There is zero reason to ever use it again.

If you're just trying to try out Ubuntu I wouldn't install it like this as it runs great in a virtual machine and whether you use the Windows Hyper-V or VirtualBox you will be just fine. I would try it out and use it that way. Dual booting is always terribly kludgy and error-prone in regard to the boot loader. The true answer is "NEVER DO THIS!" there is no reason that makes any sense... You're one Ubuntu or Windows Update from things on one OS or the other not working.

+ 2

Mojtaba Mokhtari

12/23/23, 10:06 AM

but before I would install Window 10, the GRUB is properly showing Windows 7 and Ubuntu.

sean

12/23/23, 3:17 PM

You're going to get into the realm of "Undefined Behavior" very quickly with a tri-boot system. Windows only tests their boot loader with dual boot configurations, and so does Ubuntu (or really GRUB). Functionally, there is no reason to have Windows 7 on the machine and just running Windows 10/Ubuntu is a supported & tested configuration. Once you get off that dual boot you're doing something that none of these guys test... That can be fine, but if it doesn't work don't be surprised.

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