PowerShell: get the real last boot time and uptime
The script
Read LastBootUpTime from Win32_OperatingSystem. Note that with Fast Startup enabled, a shutdown and power-on is a resume, not a boot, so a machine can show weeks of uptime while its user insists they turn it off every night. Only a restart resets the counter.
$os = Get-CimInstance Win32_OperatingSystem
[PSCustomObject]@{
LastBoot = $os.LastBootUpTime
Uptime = (Get-Date) - $os.LastBootUpTime
}Notes before you run it
- "I shut it down every night" and an uptime of 40 days are both true when Fast Startup is on.
shutdown /shibernates the kernel;shutdown /ractually reboots. - Pending-update problems and slow machines that a restart would fix hide behind this: check uptime before believing a machine has recently rebooted.
- Disable Fast Startup fleet-wide with the registry value
HiberbootEnabled = 0underHKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Powerif you want shutdowns to mean shutdowns.
Run it on every machine, not one at a time.
Save any of these as a command in Moorfox and run it on a machine in one click, output and exit code captured, with no PSRemoting or WinRM setup. The agent runs it locally and reports back, even over the internet.