I'm trying to install Virtualbox on my Ubuntu 18.04 but I encountered some problems because of Secure Boot. So I'm following this tutorial which seems a good solution.

But here is my problem : When I reboot and choose 'Enroll MOK' on the 'blue window', I enter my password, but it always fail... I tried many times, and everytime I remove .priv and .der files to re-generate them with openssl command, but agains and again :

"The password doesn't match"

I'm pretty sure that I enter the same password when I generate files with mokutil command.

Am I missing something ?


After several attempts, I finally found a solution... The password cannot be longer than x characters, and I think is 5, according to this post.

I find it strange, but I hope it can help someone !

  • Well the prompt for password during the NVidia driver install complains if I try to use a short password: "The Secure Boot key you've entered is not valid. The password used must be between 8 and 16 characters." – Gunnar Forsgren - Mobimation Apr 25 '19 at 10:00
  • 1
    It asks you for the secure boot password, this post is about a MOK password. I think you've choose your secure boot password when you installed your OS. – Rémi Apr 25 '19 at 10:14

It worked for me in this way:

Use letters (I had nine letters) instead of numbers (like it is indicated in many examples) for the temporal password, when it is created using:

sudo mokutil --disable-validation


  • Reboot.

  • Press any key when the MOK management blue screen is displayed.

  • Select "Change Secure Boot state".

  • Enter, one at at time, the letter of your pasword at the asked position and hit enter.

  • After several letters (not all were tested), answer yes to "disable Secure Boot".

  • Start the PC.

  • Open a terminal in your Linux environment.

  • Load the vboxdrv modules with

    lsmod | grep vboxdrv
  • The following message is displayed when the modules are correctly loaded

    vboxdrv               454656  3 vboxnetadp,vboxnetflt,vboxpci

And that's it!


I had the same problem and it enventually worked by typing the password as if I had a qwerty keyboard in the MOK manager, though it is an azerty one... (note that I used a short password as suggested, I don't know if this counted as well...)

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