"Booting in insecure mode" when secure boot is turned on

Question

I have a dual boot (UEFI) Windows 10 Pro and Ubuntu 16.04. During Ubuntu install IT asked me to turn off secure boot, so I did it, using the installer. When I finished installation, I turned secure boot on again in BIOS, but I keep getting this:

Booting in insecure mode_

Every time I start my PC, before entering GRUB. I checked it on Windows and it says that secure boot is enabled, same as my BIOS. I am attaching a photo of my BIOS config:

How can I turn secure boot back on so Ubuntu will see it as enabled? Is there any way to get rid of this annoying message? Thanks in advance ;-)

Solution

I know that Dell ships their Linux systems with a variable set that disables validation: https://bugzilla.redhat.com/show_bug.cgi?id=1544794

The solution is to enable validation in that case. Perhaps this is what you're seeing? Try running:

mokutil --enable-validation

Comments

[ikurek]

How do I check IT?

[ikurek]

I got this: 0000000 0006 0000 0001 / 0000005

[Rod Smith]

In that case, it looks like your system is booted with Secure Boot active, and the message to the contrary at boot time is in error. At least, I'd say that's about 90% likely to be the case; it could also be you've got some other exotic bug that's causing Secure Boot to appear to be active in the firmware and in two OSes when in fact it's not active. You could always try testing it by attempting to boot something that's not signed; you should get an error message or possibly just a failover into the next boot option.