Calculate LDAP DateTime from FileTime

Convert-LdapDateTime.ps1

#Get-aduser myUsername -Properties lastlogondate, lastlogon, lastlogontimestamp | select lastlogondate, lastlogon, lastlogontimestamp
#LastLogonDate is a DateTime
#LastLogon is a Long / Int64
#LastLogonTimestamp is a Long / Int64
#NB: values may differ slightly, as LastLogonDate/LastLogonTimestamp is cached for up to 2 weeks before replicating to all servers, whilst LastLogon is updated instantly but only on the users logon server: https://serverfault.com/a/734641/137255

$lastLogonTimeLdap = 131723288263417819

#The official way
[DateTime]::FromFileTimeUtc($lastLogonTimeLdap)
#01 June 2018 12:13:46

#The DIY way (useful to know if you need to replicate in other languages)
[DateTime]::MinValue.AddYears(1600).AddMilliseconds(($lastLogonTimeLdap / 10000))
#01 June 2018 12:13:46

# NB: ([DateTime]::MinValue.AddYears(1600) = 1601-01-01 00:00:00)
# 1601-01-01 00:00:00 = Win32's Epoch
# See https://blogs.msdn.microsoft.com/oldnewthing/20090306-00/?p=18913 for explanation