PowerShell can easily retrieve important operating system details such as the build number and version by reading the appropriate registry values:
# read operating system info Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion' | # pick selected properties Select-Object -Property CurrentBuild,CurrentVersion,ProductId, ReleaseID, UBR
Some of these values use crypting formats, though. The InstallTime registry key, for example, is just a very large integer.
PS> $key = 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion' PS> (Get-ItemProperty -Path $key).InstallTime 132119809618946052
As it turns out, these are the ticks, and by using the [DateTime] type and its FromFileTime() static method, you can easily convert ticks to a meaningful install date:
PS> $key = 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion' PS> $ticks = (Get-ItemProperty -Path $key).InstallTime PS> $date = [DateTime]::FromFileTime($ticks) PS> "Your OS Install Date: $date" Your OS Install Date: 09/03/2019 12:42:41
You can use FromFileTime() whenever you encounter ticks. The Active Directory, for example, stores Dates in this format, too.
