Gather Computer Real LastLogon

gistfile1.txt

<# 
At the 1st DC processed, we will have all the computers and their lastLogon in a ArrayList.
At the following DCs processed, only the LastLogon property of the computer being processed will be updated
#>

# Gathering DCs list
$DCList = Get-ADDomainController -Filter *

# Gathering Computer List
$AllComputers = Get-ADComputer -Filter *

# Initiate a ArrayList (or Better a GenericList), cause these types of object have a method called .add()
$Result = [System.Collections.Generic.List[object]]::new()  # or [System.Collections.ArrayList]::new()

ForEach ($Computer in $AllComputers)
    {
    # Initializes LastLogon to $null as starting point
    $TargetComputerLastLogon = $null
    Foreach($DC in $DCList)
        {
        Try
            {
            #  Retrieve the value of the lastLogon attribute from a DC (each DC in turn)
            $LastLogonDC = Get-ADComputer -Identity $Computer.SamAccountName -Properties lastLogon -Server $DC.Name
            # Convert value to date/time format
            $LastLogon = [Datetime]::FromFileTime($LastLogonDC.lastLogon)
            # If the value obtained is more recent than that contained in $TargetComputerLastLogon
            # lthe variable is updated: this ensures to have the most recent lastLogon at the end of the processing
            If ($LastLogon -gt $TargetComputerLastLogon)
                {
                $TargetComputerLastLogon = $LastLogon
                }
 
            # Clean up var
            Clear-Variable LastLogon
            }

        Catch 
            {
            Write-Host $_.Exception.Message -ForegroundColor Red
            }
        }
        # Building a PSObject
        $LastLogonObj =  @{
            SamAccountName = $TargetComputer
            LastLogon = $TargetComputerLastLogon
            }
        # Adding the previous PSObject to $Result
        $Result.Add($LastLogonObj)
    }

# Display the Result
$Result
# Or export in a .csv file
$Result | Export-Csv -Path Path\to\LastLogn.csv -NoTypeInformation