Have a situation where outlook 2010 is continuously prompting users for credentials. The exchange 2010 environment lives in a separate forest and the users are connected with linked accounts and external domain trusts. Problem did not start occurring until the original 2003 domain controller, dns, dhcp, was replaced with two new 2008r2 servers. It appears that mail continues to flow in and out just fine even if you ignore the prompt. Problem is also not consistent across all users at the office. A few have not even experienced the problem at all. The basics have already been attempted such as clearing out passwords in the accounts manager and new outlook profiles. Exchange 2010 and outlook clients are configured for outlook anywhere basic authentication.