System
Power Efficiency Report
Windows can generate a Power Efficiency Report as a standalone HTML diagnostic file at %WinDir%\System32\energy-report.html after running powercfg /energy. The report embeds captured analysis results about sleep states, timer requests, USB suspend behavior, device power policy, and service or driver findings from that specific scan, so it often becomes outdated while still looking authoritative. Kudu removes the old generated report file so a fresh diagnostic run produces current results without touching power plans, device settings, accounts, or personal data.
Why clean Power Efficiency Report?
- An old energy-report.html reflects the system state from a past powercfg scan, so users may chase battery drain or sleep issues that no longer exist because they are reading stale diagnostics
- Repeated troubleshooting runs overwrite the same report logic but often leave one forgotten HTML file in System32, making it easy to open an outdated copy and misread current device or driver behavior
- Power setting changes, driver updates, and firmware fixes can invalidate earlier warnings, and the visible symptom is a report that still flags problems already resolved after recent maintenance
- Support sessions often rely on the timestamped contents of the report, so keeping an obsolete file causes confusion when the findings do not match what Event Viewer, battery usage, or modern sleep behavior shows now
- The report is a generated artifact rather than a live database, so deleting it does not remove any diagnostics history from Windows itself; it simply clears a stale snapshot that can mislead later troubleshooting
- If the HTML file is shared or reopened months later, users may assume current services, devices, or timer requests are responsible for poor standby life when the observable mismatch is that the machine now behaves differently than the report claims
What gets cleaned
Cache paths Kudu targets
Windows
%WinDir%/System32/energy-report.html |
Frequently asked
Common questions about Power Efficiency Report
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