Windows removed from grub menu during update of grub/kernel

Machine was updated recently without problems from 42.3 to 15.1 via DVD. Windows, on the second HD, was in grub menu as before.
Today I let package updater update lots of stuff - 100+ packages - including grub and the kernel. Afterwards Windows is no longer on the grub menu.

This only a minor inconvenience for me - I can boot windows from the machine’s boot menu so I probably won’t bother to fix it. But it looks like something is amiss with the grub update.

What exactly is in Grub’s menu? Is it two pages, with only two choices on page 1?

From the command line (as root user) can you run;


If it shows windows present, then can you check YaST bootloader on the last tab that probe foreign os is checked.

Yes. 2 choices - default SUSE and advanced. Selecting advanced gives, IIRC, 3 kernels, 2 lines each. The same as another machine, which only has SUSE.

I’ll check os-prober and the YaST bootloader setting next time I turn the machine on.

I turned it on and … Windows was back on the boot menu!

Isn’t that odd? I had rebooted at least once after it disappeared and then I booted into Window by calling the bios boot menu (F12) to check it was still there. Later I booted it into the grub menu to compare the kernel versions with another machine, but didn’t load SUSE.

os-prober reports /dev/sdb:Windows 10:Windows:chain
Probe foreign OS is selected

Perhaps the disk was physically stuck until I used it?

Disappearance of Windows’s boot option in GRUB has happened to me many times.

I do the same as malcolmlewis suggests: run the os-prober, check the “Probe foreign OS” box in Yast’s bootloader installation section, and reinstall the boot loader.

In some cases, a simple reboot after a big update has helped.

The os-prober of 15.0 and earlier didn’t work well.

Well for me it has been the first time. Just so glad I saw the post today as I was about to ask the question. Whatever happened to others, it does appear my problem started after an update earlier in the day so grateful thanks to all once more for excellent advice and the simple solution.

No, I’d never had it just disappear before. I knew about os-prober and I’ve used yast before to set up the grub menu when adding new Windows partitions - but some time ago.

I’d assumed that the grub menu would only change during an update, or if you do it yourself using yast. Surely it doesn’t probe for new OSes every time you boot the machine?

Yes, that’s about right. The menu is generated by running

grub2-mkconfig -o /boot/grub2/grub.cfg

When you change something with Yast bootloader, that is automatically run. Or when you update your system, it might be run (depending on what was updated). Or you can run that at the command line. Apart from that, the menu should not change.

If you have more than one linux system installed, then you do really need to be aware which of those controls the boot menu.