Why

I’m cleaning up an Active Directory domain, and needed to get an idea of how many computers are in use vs. inactive.

Script

I’m doing some other spluking with this, so I’m going to stick a list of all computers in a variable. I’m including the lastLogonTimeStamp we’re going to use to figure out which computers are active.

$rawComputers = Get-ADComputer -Filter * -Properties lastLogonTimestamp

lastLogonTimeStamp is represented as a file timestamp, not a DateTime. Let’s fix that an get rid of some extra properties.

$computers = $rawComputers | select Name, DistinguishedName, Enabled, @{Name="Timestamp"; Expression={[DateTime]::FromFileTime($_.lastLogonTimestamp)}}

How many have a lastLogonTimeStamp more than 30 days old?

$cutoff = [DateTime]::Now.Subtract([TimeSpan]::FromDays(30))
($computers | ? {$_.Timestamp -lt $cutoff}).Count

Let’s export that to a CSV.

$computers | ? {$_.Timestamp -lt $cutoff} | Export-CSV -NoTypeInformation -Path InactiveComputers.csv

Resources

• Ask the Directory Services Team - “The LastLogonTimeStamp Attribute” – “What it was designed for and how it works”

Written by Eric Haskins, maker of things.