We use Exchange 2003 and have quite a few users using OWA. When they log in, they are checking the remember my password check box. However, next time they log on, they are being asked again.
In addition, each time they click on a mail to open it or try to open an attachment, they are again beingasked for they username and password.
It is not affecting all users, so I presume it is a local machine setting rather than on the Exchange Server itself.