Fix Broken Dependencies After Upgrading to Ubuntu 26.04 LTS

📖 ~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

System upgrade completes but apt reports unmet dependencies and held packages. New security and kernel updates cannot be installed.

Environment & Reproduction

Usually appears after interrupted do-release-upgrade, third-party repository conflicts, or mixed package origins from prior Ubuntu releases.

Root Cause Analysis

Package versions from old repositories do not satisfy Ubuntu 26.04 dependencies. Some transitional packages are missing or held.

Quick Triage

Run sudo apt –fix-broken install and sudo apt-mark showhold. Confirm repository set with grep -R ‘^deb ‘ /etc/apt/sources.list /etc/apt/sources.list.d.

Step-by-Step Diagnosis

Inspect solver output using sudo apt -o Debug::pkgProblemResolver=yes dist-upgrade. Review /var/log/dist-upgrade/main.log for failing package chains.

Solution – Primary Fix

Disable incompatible third-party entries, run sudo apt update, then sudo apt –fix-broken install and sudo apt full-upgrade. Remove blockers with sudo apt remove package-name when necessary.

Solution – Alternative Approaches

Use Ubuntu’s old-releases mirror only for temporary retrieval of missing transitional packages, then switch back to official 26.04 sources.

Verification & Acceptance Criteria

sudo apt check returns no dependency issues. sudo apt full-upgrade completes with zero held broken packages.

Rollback Plan

Restore /etc/apt from backup and use Timeshift or filesystem snapshot rollback if dependency state becomes unrepairable.

Prevention & Hardening

Before release upgrades, disable PPAs and non-Ubuntu repositories. Keep a package list export using dpkg –get-selections.

Related Errors & Cross-Refs

Common related errors: ‘Depends: X but it is not installable’ and ‘held broken packages’. Cross-reference do-release-upgrade logs.

Related tutorial: View the step-by-step tutorial for Ubuntu 26.04 LTS.

View all Ubuntu 26.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Ubuntu release upgrade documentation, apt preferences manual, and sources.list format reference.