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I am stuck in Ubuntu 20.04 because my Windows 10 can't start. When I click on Windows (UEFI) to boot windows, it shows a black blank screen and that's it forever. I have to shutdown from there to be able to access grub menu again and Ubuntu when I power on. I have tried upgrading grub and many other tricks that I don't remember, and nothing seems to work. I have installed grub2 and run sudo update-grub and sudo update-grub2, but it didn't seem to help.

Current grub boot menu:

enter image description here

karel
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Moobius
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  • @karel, I just tried the answers on that page but nothing too helpful. I had the custom.cfg file exactly as it's there, so I guess I have tried this before. I can see grub menu and the Windows (UEFI) option. Just my Windows comes out blank and can't start. – Moobius Feb 05 '21 at 08:37
  • Grub only boots working Windows. And Fast start up must be off, Windows not hibernated nor UEFI Secure Boot on. http://askubuntu.com/questions/843153/ubuntu-16-showing-windows-10-partitions & https://askubuntu.com/questions/145902/unable-to-mount-windows-ntfs-filesystem-due-to-hibernation If UEFI you should be able to directly boot into Windows from UEFI boot menu & change settings. Or you can use your Windows repair/recovery disk. – oldfred Feb 05 '21 at 15:22

1 Answers1

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Try this... In a terminal:

sudo grub_mkconfig

Reboot and try win...

Below you will find part of the terminal's "info grub" output... my research reference.

Good luck!!

6.1 Simple configuration handling

The program 'grub-mkconfig' (*note Invoking grub-mkconfig::) generates 'grub.cfg' files suitable for most cases. It is suitable for use when upgrading a distribution, and will discover available kernels and attempt to generate menu entries for them.

'grub-mkconfig' does have some limitations. While adding extra custom menu entries to the end of the list can be done by editing '/etc/grub.d/40_custom' or creating '/boot/grub/custom.cfg', changing the order of menu entries or changing their titles may require making complex changes to shell scripts stored in '/etc/grub.d/'. This may be improved in the future. In the meantime, those who feel that it would be easier to write 'grub.cfg' directly are encouraged to do so (*note Booting::, and *note Shell-like scripting::), and to disable any system provided by their distribution to automatically run 'grub-mkconfig'.

The file '/etc/default/grub' controls the operation of 'grub-mkconfig'. It is sourced by a shell script, and so must be valid POSIX shell input; normally, it will just be a sequence of 'KEY=value' lines, but if the value contains spaces or other special characters then it must be quoted. For example: end_______

Nadacop
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