🟠 High   ⏱ 5–30 min  Last verified: 19 May 2026
Affected versions: Windows Server 2012 R2

📖 ~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

Unexpected reboots occur with Kernel-Power events.

Environment & Reproduction

Seen after BIOS/chipset updates.

Get-WinEvent -FilterHashtable @{LogName='System'; Id=41} -MaxEvents 20

Root Cause Analysis

ACPI transition bug conflicts with platform firmware.

Quick Triage

Correlate reboot timeline to firmware deployment.

Step-by-Step Diagnosis

Validate power settings and PnP changes.

Illustrative mockup for windows-server-2012-r2 — terminal_or_powershell
ACPI reboot diagnostics — Illustrative mockup — Progressive Robot

Solution — Primary Fix

Apply vendor hotfix pair and conservative power profile.

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pnputil /add-driver C:DriversChipset*.inf /install
Illustrative mockup for windows-server-2012-r2 — event_or_log_viewer
Power state stability confirmed — Illustrative mockup — Progressive Robot

Solution — Alternative Approaches

Move workloads to peer hosts during remediation.

Verification & Acceptance Criteria

No unexpected reboot for seven days.

Rollback Plan

Revert BIOS/chipset bundle to validated version.

Prevention & Hardening

Treat firmware and chipset as a tested release unit.

Associated with bugcheck 0x9F and WHEA noise.

Related tutorial: View the step-by-step tutorial for Windows Server 2012 R2.

View all Windows Server 2012 R2 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

ACPI and firmware lifecycle guidance.

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