Windows 8 PowerCfg -Energy

PowerCfg -Energy for Troubleshooting Sleep Problems

Windows 8 has built-in utility called PowerCfg; when troubleshooting sleep problems, I find its little-known switch -Energy invaluable.

Topics for Windows 8 PowerCfg -Energy

• Using PowerShell to Run PowerCfg -Energy
• Examining the Energy-report.html
• PowerCfg -Energy Analysis Results
• Troubleshooting Sleep Problems with PowerCfg

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Guy’s Rule for Laptops Notebooks and Tablets

Every mobile computer exhibits at least one of these Power Management issues.

• Won’t awaken up from sleep or hibernation.
• Suddenly wakes up for no apparent reason.
• Refuses your attempt to set: Sleep, Hibernate or Standby.
• Battery life does not come close to manufacturer's claim.

Using PowerShell to Run PowerCfg -Energy

The old-fashioned way was to run built-in Windows utilities is by launching a 'DOS box' with cmd.exe; the modern way is execute all command-line programs through PowerShell.  PowerCfg with PowerShell seems particularly apt.

Here is an example:

Note 1: When you run the command, scroll down to the bottom, observe a note saying:
See C:\WINDOWS\system32\energy-report.html for more details.

Note 2: The energy-report.html file is created in the current directory, and not necessarily in the \windows\system32 folder.

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Examining the Energy-report.html

Here are more details about sleep from the resultant energy-report.html.

Platform Power Management Capabilities:

PowerCfg -Energy Analysis Results

The energy-report.html is even color coded.  Here is an example of a service that is preventing your computer from sleeping.

This warning could explain why the battery life is shorter than advertised.

Note 3: When working with PowerCfg I like to have the Device Manager open so that I can check the 'Power Management' tab of the mouse, keyboard and other devices that could bring the computer out of its slumber.

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Windows 8 PowerCfg Benefits

• I find PowerCfg quicker to use troubleshooting than the Control Panel’s Power Management GUI.
• This utility can also be used in Windows 7, but not Server 2008.
• The report reveals vital information on which devices are supposed to wake the computer.
• PowerCfg helps you to understand the inter-relationship between the sleep components.
• Experiment with PowerCfg led me to investigate group policies that were controlling sleep settings.
  Computer Configuration\System\Power Management.  (See screenshot right)

Researching More Switches with PowerCfg /?

For troubleshooting power-related problems there are several other useful switches to see the full list try: PowerCfg /?

Note 4: As with many command-line utilities you could use the /forward slash instead of the -dash.  Incidentally, the help file shows the /, where as most people perfer the -dash as used with PowerShell's parameters.

Refining PowerCfg -Energy

Research other switches reveals that -Energy itself has modifies such as -Trace and -XML (creates energy-report.xml instead of .html).  There is also a -Duration to adjust the time it takes to analyze your computer's settings.

Example of a Battery Report

Sleep Mode v Hibernate
When you close a laptop's lid the operating system cuts the power to all unneeded parts of the machine, thus conserving power.  In this sleeping mode, there is a trickle of power to the RAM so that it can restart the disk and monitor when a user presses a key.  (S3 mode in BIOS)

In the case of hibernation, the disks have to spin-up and the operating system must read the hiberfil.sys file, hence you can detect an appreciable delay before the machine is ready to accept user input.  (S4 mode in BIOS)

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Troubleshooting Sleep Problems with PowerCfg

Here are ideas to troubleshoot common sleep or premature awakening problems using PowerCfg and its switches.

Problem 1: Access Denied

The most common problem is access denied despite being and administrator, and using 'Run as Administrator'.

Solution 1a: Create another Administrator, logon as that account.

Solution 1b: Run scannow /sfc the PowerCfg.exe maybe corrupted.

Problem 2: Windows 8 Won't Sleep

This /Requests switch will display what's blocking sleep.  Once you have identified the component try:

Solution 2:

Problem 3: Computer Wakes Randomly

Solution 3 and 3a:

Problem 4: Could not open the NT Kernel Logger

I once had a message saying that PowerCfg could not run, because the logger was already running.

Solution 4:  Close Performance Monitor.

See more on Windows 8 Sleep Mode »

Summary of Windows 8 PowerCfg -Energy

Windows 8's PowerCfg has a useful switch called -Energy.  This technique is invaluable for troubleshooting sleep problems, particularly on Windows laptop or notebook or tablet mobile computers.

Microsoft Windows 8 Troubleshooting Topics

• Windows 8 Overview  • Win 8 Event Viewer  • Windows 8 Shutdown  • Windows 8 Join Domain

• Windows 8 Performance Monitor  • Windows 8 PowerCfg -Energy  • Windows 8 Sleep Problems

• Windows 8 Troubleshooting  • Windows 8 Sound Problems  • Win 8 Server Admin Tools  • Tookit