Question

I wanted a windows service I’m building to run overnight. So I changed my power options and set my computer to never sleep. Started the windows service and went home. This morning I found my computer sleeping and was curious if someone manually put it to sleep after I left. Is there a log file or some way to find the last time my computer went to sleep? I’m using a Windows 7 operating system.

Answer 1

Have you consulted Event Viewer? To start Event Viewer by using a command line

• Open a command prompt. To open a command prompt, click Start, click All Programs, click Accessories and then click Command Prompt.
• Type eventvwr.

Information about scheduled / unscheduled sleeps and reboots should be found by expanding the tree view in the left plan to Event Viewer > Windows Logs > System.

You can also get the last boot time by using the WMI service object to query the LastBootUpTime property of the Win32_OperatingSystem class. Note that the returned date is in WMI date time format which you’ll need to use tools to convert into a human readable date.

Here’s a VBScript sample:

' LastBoot.vbs
Option Explicit
Dim wmiService, objDateTime, OS
Set wmiService = GetObject("winmgmts://localhost/root/cimv2")
Set objDateTime = CreateObject("WbemScripting.SWbemDateTime")
Set OS = wmiService.ExecQuery("SELECT * FROM Win32_OperatingSystem").ItemIndex(0)
WScript.Echo OS.LastBootUpTime ' Example: 20180801131622.495364+660
objDateTime.Value = OS.LastBootUpTime
WScript.Echo objDateTime.GetVarDate ' Example: 01/08/2018 12:16:22 PM

Here’s a PowerShell example:

(Get-WmiObject Win32_OperatingSystem).LastBootUpTime
# Outputs: 20181009160558.495300+660

(gcim Win32_OperatingSystem).LastBootUpTime
# Outputs: Wednesday, 1 August 2018 12:16:22 PM

Here’s a Command Prompt example (uses PowerShell):

powershell -command "(Get-WmiObject Win32_OperatingSystem).LastBootUpTime"
REM Outputs: 20180801131622.495364+660

powershell -command "(gcim Win32_OperatingSystem).LastBootUpTime"
REM Outputs: Wednesday, 1 August 2018 12:16:22 PM

References:

• https://learn.microsoft.com/en-us/windows/desktop/cimwin32prov/win32-operatingsystem
• http://powershell-guru.com/powershell-tip-7-convert-wmi-date-to-datetime/
• https://www.thewindowsclub.com/find-system-uptime-windows