Debian 9 Unmet Dependencies During full-upgrade

📖 ~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

full-upgrade halts with unresolved package requirements and partial transaction state.

Environment & Reproduction

Often triggered by mixed repositories, held packages, or stale package indexes.

Root Cause Analysis

Dependency graph cannot be satisfied due to version constraints across enabled sources.

Quick Triage

List held packages and detect repository pinning conflicts before forcing changes.

Step-by-Step Diagnosis

Trace dependency blockers and evaluate candidate versions from each repository.

Solution – Primary Fix

Normalize repositories, clear broken state, and resolve the blocking package set.

Solution – Alternative Approaches

Use targeted package downgrades or temporary pinning to restore consistency.

Verification & Acceptance Criteria

full-upgrade runs to completion with no unmet dependency messages.

Rollback Plan

Reinstate prior source lists and package selections if upgrade path remains unstable.

Prevention & Hardening

Control repository sprawl and enforce package-pinning governance.

Related Errors & Cross-Refs

Related to held broken packages and cannot configure package dependency loops.

Related tutorial: View the step-by-step tutorial for Debian 9.

View all Debian 9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Debian package dependency resolution and apt policy documentation.