[Management.ManagementDateTimeConverter]::ToDateTime($WMIDate)When using the Get-WmiObject cmdlet datetimes are returned using the Common Information Model (CIM) format. This command will convert these to standard datetime objects.
PS C:\> $WMIDate = (Get-WmiObject -Class Win32_OperatingSystem).LastBootUpTime >> [Management.ManagementDateTimeConverter]::ToDateTime($WMIDate) Tuesday, April 9, 2019 12:54:35 PM