📖 ~1 min read
Table of contents
Symptom & Impact
Users authenticate successfully but land on a black screen with no usable desktop session.
Environment & Reproduction
The failure appears after driver updates, display manager changes, or interrupted graphics package upgrades.
Root Cause Analysis
Broken Xorg configuration, incompatible graphics drivers, or corrupted user session files can block Unity startup.
Quick Triage
Switch to a TTY, verify disk space, and test login with a secondary user account.
Step-by-Step Diagnosis
Inspect Xorg and display manager logs and confirm graphics package integrity before modifying configs.
Solution – Primary Fix
Reinstall core desktop and graphics packages, reset user session config, and restart the display manager.
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Solution – Alternative Approaches
Boot with recovery mode, use a generic driver profile, and reapply vendor drivers only after stability checks.
Verification & Acceptance Criteria
Graphical login opens the desktop reliably across multiple reboots with normal GPU acceleration.
Rollback Plan
Revert to previous graphics stack or kernel from GRUB advanced options if regressions persist.
Prevention & Hardening
Avoid abrupt power-offs during upgrades and snapshot systems before major graphics driver changes.
Related Errors & Cross-Refs
Commonly associated with login loops, failed lightdm service starts, and GLX initialization errors.
Related tutorial: View the step-by-step tutorial for Ubuntu 16.04 LTS.
View all Ubuntu 16.04 LTS tutorials on the Tutorials Hub →
Browse all common problems & solutions on the Tutorials Hub.
References & Further Reading
Refer to Ubuntu desktop recovery guidance and vendor driver support documentation.
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