π ~1 min read
Table of contents
Symptom & Impact
NVIDIA settings cannot find the GPU, external displays fail, and performance drops to software rendering after boot.
Environment & Reproduction
Seen on systems with UEFI Secure Boot enabled after installing proprietary drivers through ubuntu-drivers or Software & Updates.
Root Cause Analysis
Kernel module is blocked by Secure Boot when module signature is missing or Machine Owner Key enrollment did not complete.
Quick Triage
Check module state with lsmod | grep nvidia and dmesg | grep -i -E ‘nvidia|secure boot|lockdown’.
Step-by-Step Diagnosis
Run mokutil –sb-state and sudo modprobe nvidia. Validate package set with dpkg -l | grep nvidia-driver.
Solution – Primary Fix
Reinstall recommended driver using sudo ubuntu-drivers autoinstall, then complete MOK enrollment at reboot. After reboot, verify with nvidia-smi.
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Solution – Alternative Approaches
Temporarily disable Secure Boot in firmware for testing, or use the open-source nouveau driver until signature enrollment succeeds.
Verification & Acceptance Criteria
nvidia-smi returns GPU details and no Secure Boot rejection appears in dmesg. GNOME About reports hardware acceleration.
Rollback Plan
Remove proprietary stack with sudo apt purge ‘nvidia-*’ and restore default graphics packages. Re-enable prior boot settings.
Prevention & Hardening
Use ubuntu-drivers recommended packages only and finish MOK enrollment immediately after installation.
Related Errors & Cross-Refs
Related logs include ‘Lockdown: unsigned module loading is restricted’. Cross-reference DKMS build failures.
Related tutorial: View the step-by-step tutorial for Ubuntu 26.04 LTS.
View all Ubuntu 26.04 LTS tutorials on the Tutorials Hub β
Browse all common problems & solutions on the Tutorials Hub.
References & Further Reading
Ubuntu NVIDIA documentation, mokutil manual, and UEFI Secure Boot guidance.
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