Find users who have never logged in

PS > Get-Aduser -SearchBase 'OU=User Accounts,DC=contoso,DC=com' -SearchScope Subtree -Properties Name, LastLogonTimestamp | Sort-Object LastLogonTimestamp | Format-Table

Users who have never logged in will appear at the top with no LastLogonTimestamp

I used this recently and found a dozen or so students who had accounts but ended up not attending