Failed to start Network Manager on boot

📖 ~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 boots without network connectivity managed by NetworkManager.

Environment & Reproduction

Ubuntu 16.04 desktops or servers using NetworkManager with conflicting config.

Root Cause Analysis

Service unit misconfiguration, plugin conflicts, or invalid interface configuration prevents startup.

Quick Triage

Check systemctl status and journal entries for immediate failure reason.

Step-by-Step Diagnosis

Review NetworkManager config, dependencies, and interface ownership state.

Solution – Primary Fix

Correct invalid config, reload daemon units, and restart NetworkManager service.

Solution – Alternative Approaches

Temporarily use netplan or ifupdown-managed interfaces for critical connectivity.

Verification & Acceptance Criteria

NetworkManager starts cleanly and interfaces obtain expected connectivity.

Rollback Plan

Restore previous network configuration files if connectivity degrades.

Prevention & Hardening

Validate network config changes in staging and track service health on boot.

Related Errors & Cross-Refs

network-manager.service failed and device not managed 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

Ubuntu NetworkManager administration and troubleshooting documents.