Can i update my windows OS using windows update assistant on a dual booted device?

I have a dual-booted laptop with windows10 and ubuntu. they are separate partitions on a single Hard drive my current windows version is windows 10 1909 and I have an update to windows10 21h2 on windows update assistant. if I download and install that update does it affect my laptop or my grub boot menu how do I update windows?

Solution 1:

There's a difference between UEFI installations and Legacy/BIOS installations. Problems may occur with the latter and rarely if ever with the former.

With UEFI installations typically the Windows feature updates change the boot order to Windows, for convenience, because it needs several reboots to finish. It's just a matter of opening UEFI settings > Boot and change it back to "Ubuntu".

With Legacy/BIOS installations it may replace Grub and, in the past, some instances of "broken" partition table have been reported, but not lately. Grub needs to be reinstalled if the Windows feature update installation replaced it with the Windows bootloader.

Assuming you're using a modern UEFI computer (anything from at least 2012 and newer) and the dual-boot has been properly set in UEFI mode you have nothing to worry about. Worse case scenario is only the minor inconvenience of changing one firmware setting back to what it was.