Clock Drift in Dual Boot on Ubuntu 24.04 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 time is wrong after switching between operating systems.

Environment & Reproduction

Dual-boot setups commonly show timezone offset on reboot.

Root Cause Analysis

RTC handling differs between local time and UTC expectations.

Quick Triage

Check time sync status with timedatectl.

Step-by-Step Diagnosis

Review ‘RTC in local TZ’ and NTP state in timedatectl output.

Solution – Primary Fix

Set Ubuntu to use UTC hardware clock with timedatectl set-local-rtc 0 and enable NTP using timedatectl set-ntp true.

Solution – Alternative Approaches

If required, configure the other OS to use UTC for RTC consistency.

Verification & Acceptance Criteria

Time remains correct after two full reboot cycles.

Rollback Plan

Revert with timedatectl set-local-rtc 1 –adjust-system-clock if policy requires local RTC.

Prevention & Hardening

Keep NTP enabled and avoid manual clock edits.

Related Errors & Cross-Refs

Related: TLS certificate warnings caused by incorrect system time.

Related tutorial: View the step-by-step tutorial for Ubuntu 24.04 LTS.

View all Ubuntu 24.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

man timedatectl and Ubuntu time synchronization docs.