Setting up a MOK on Ubuntu will it break dual boot Windows?

RavenLunatic · Saturday at 15:57

I have managed to break secure boot in my Ubuntu install after updating the Nvidia driver via software and updates 3rd Party drivers.

Every time I try to upgrade to Ubuntu 25.10 it asks me to setup a MOK.

My concern is it might break my Windows install on the same SSD which also requires secure boot and is working fine.

I want to keep my current Ubuntu install as I have made a load of custom modifications over the last year that would be a pain to redo.

Will setting up MOK break my Windows install?

RavenLunatic · Monday at 14:40

Could not find an answer other than it "should not/might not" break Windows secure boot from AI.

If it works it might cause another problem, as it could add Window's to grub which will increase boot time because grub insists on scanning all my SSD's for operating systems at every boot.

Not sure what to do.

RavenLunatic · Monday at 15:28

I am using the BIOS EFI loader
Both OS's are on the same SSD partitions are 1GB EFI bootloader FAT, 256GB Ubuntu EXT4, 1TB Windows 11 NTFS, and a recovery partition.
The only bootloader (grub) runs when I select Ubuntu from the BIOS boot menu.

My problem seems to be a failed install of Virtual box, dpkg keeps trying to run the installer every time I attempt to upgrade landing me with the mok setup.

RavenLunatic · 2025-11-04T09:42:53+0000

I was able to finally remove Virtual Box partial install doing the following thanks to Eve online discord

sudo apt-get remove --purge virtualbox-7.2
debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable

sudo fuser -v /var/cache/debconf/config.dat
USER PID ACCESS COMMAND/var/cache/debconf/config.dat: root 6689 F.... frontend

sudo kill -9 6689

sudo rm /var/cache/debconf/*.dat

sudo apt-get remove --purge virtualbox-7.2

and Virtual box and MOK was gone :-)

RavenLunatic · 2025-11-04T13:19:53+0000

I was about to go ahead kill or cure style, but it took allot of effort to get Windows 11 back on my system as for what ever reason the Windows 11 installer always crashes during the update stage presumably due to some driver error. I had to install windows 10 with drivers then do an upgrade to 11 which failed a couple of times before eventually working.

Trying to remove the block on Ubuntu and potentially breaking it was the least worse possible outcome.

I can run Virtual box on Windows, so I still have that functionality, and I now have a working Ubuntu install for everything else.