Find Users without a Manager in Active Directory

1Get-ADUser -SearchBase "ou=users,dc=contoso,dc=com" -Filter * -Properties Name, EmployeeNumber, UserPrincipalName, Manager | where {$_.Manager -eq $null} | ft Name, EmployeeNumber, UserPrincipalName, Manager

Because “Manager” is an extended attribute in Active Directory you can’t use -Filter {Manager -notlike “*”} like you would with basic attributes