One of our Mac users who is on OS X Leopard is having a problem printing to a networked printer on our Windows network. He could print OK a few weeks ago but recently when he presses print he gets asked for his network credentials but despite putting them in he still can not print. The job then gets paused in the print queue on his Mac and if I resume printing a message comes and goes that says NT_STATUS_LOGON_FAILURE. I've tried printing to the same printer from another Mac that has OS X Lion installed and that prints without any problems. Any ideas what might be causing the problem and what things I can check on the OS X Leopard computer? Thanks.