Ubuntu 18.04 LTS GRUB menu missing after dual-boot changes

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Boot options disappear, limiting recovery and alternate OS access.

Environment & Reproduction

Dual-boot workstation after partitioning or OS reinstall changes.

Root Cause Analysis

GRUB config not regenerated or hidden timeout forces direct boot.

Quick Triage

Check current boot mode and EFI entries from firmware tools.

Step-by-Step Diagnosis

Review grub.cfg generation outputs and os-prober detection results.

Solution – Primary Fix

Reinstall GRUB and update configuration with correct defaults.

Solution – Alternative Approaches

Set temporary firmware boot target for emergency OS access.

Verification & Acceptance Criteria

All intended boot entries appear and start successfully.

Rollback Plan

Restore backup EFI files and previous GRUB defaults.

Prevention & Hardening

Keep rescue media and snapshot EFI partition before changes.

Related Errors & Cross-Refs

Differentiate hidden menu behavior from corrupted GRUB binaries.

Related tutorial: View the step-by-step tutorial for Ubuntu 18.04 LTS.

View all Ubuntu 18.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

GNU GRUB docs and Ubuntu dual-boot maintenance guides.