0

I have dual boot on my PC: Ubuntu 21.04 and Windows 10. The last Windows 10 update broke the GRUB boot menu: I was unable to boot Ubuntu (same error like this question). Then I discovered and used successfully the boot-repair utility to boot again in Ubuntu. I was having no problems, until ... I had to log again in Windows. After I boot Ubuntu and restart, I have the GRUB menu. After I boot Windows, I have to repair GRUB again.

How could I cope with this? Is there any way to permanently repair GRUB? Prevent Windows from accessing its settings?

Peter T
  • 1
  • When dual-booting with Windows, disabling its Fast Startup feature is a MUST. So, start with that. Additionally you need to understand that any Windows feature update - those huge update packs that take a long time to install and several reboots - always change the UEFI boot order back to Windows. When it happens it's ONLY a matter of changing it back to "Ubuntu", no Boot-Repair needed. – ChanganAuto Aug 22 '21 at 12:39
  • Thanks for your comment: this might help me in future. I note the boot order change, this sounds like a good practice indeed.

    Well for now, I have disabled Fast Startup feature, as you have suggested, and repaired the boot again. After booting Windows, GRUB has been broken again. Also, I have tried with using the "purge GRUB" option: same behavior again, unfortunately.

     – Peter T Aug 22 '21 at 13:24
  • Please stop messing with Grub. Whenever Windows boots directly it means the boot order in UEFI (unrelated to Grub) has been changed. Open UEFI settings > Boot and change it back to "Ubuntu" where it now says "Windows bootloader manager".\ – ChanganAuto Aug 22 '21 at 13:27
  • Well, this is not the case: in boot order, the second priority option (after USB Hard Disk) is "Hard Disk: ubuntu" and in "Hard Disk drive BBS Priorities", I have: Boot Option 1: Ubuntu, Boot Option 2: Windows. When boot menu is broken, it tries to boot with the first boot option, fails, and switches to the second. – Peter T Aug 22 '21 at 13:45
  • There are 2 different settings to account for. One is the drive order > Should be set with the drive containing the ESP as the first priority; and another for the actual OS boot order (OS entries read from the .efi files in the ESP) – ChanganAuto Aug 22 '21 at 13:48
  • In Windows, have you installed a driver/software that allows you to read/write to Linux ext2/3/4 partitions? If so, remove it asap, as it's corrupting your Linux/Ubuntu. – heynnema Aug 22 '21 at 14:12
  • Some computers (HP for one), do not seem to recognized UEFI settings made by efibootmgr. It boots once & then it resets to Windows first. Maybe syncing Windows BCD. But most are able to go into UEFI settings & boot tab (not UEFI boot menu) and change boot order there. – oldfred Aug 22 '21 at 15:30
  • Thanks for the latest comments, but once again, the computer is clearly trying to boot the ubuntu boot manager, then is failing (error message as the one in the link from my question), and only then the Windows boot manager. And no, at the moment this happened for a first time, I didn't install anything in particular, just a (major) windows update. – Peter T Aug 22 '21 at 17:29
  • wild guess but what if you made the ubuntu grub file immutable using 'sudo chattr +i

    https://www.tecmint.com/chattr-command-examples/

     – pierrely Aug 23 '21 at 09:11

0 Answers0