How to use Outlook policy to control credential prompts when connecting to an Exchange Server mailbox

How to access this setting varies, depending on the version of Outlook being used. When in the Exchange account settings, click More Settings… and then click the Security tab.

Note In Outlook 2003 this setting is called Always prompt for user name and password. In Outlook 2007, Outlook 2010 and Outlook 2013, the setting is called Always prompt for logon credentials. To deploy the policy setting for all users, follow these steps.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756 How to back up and restore the registry in Windows

1. Click Start, click Run, type regedit, and then click OK.
2. In the Registry Editor, locate the following key for Outlook 2013:
   
   HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\xx.0\Outlook\Security
   
   Where xx.0 is 15.0 for Outlook 2013, 14.0 for Outlook 2010, 12.0 for Outlook 2007, and 11.0 for Outlook 2003
3. Point to New, and then click DWORD Value.
4. Type PromptForCredentials as the name of the new registry entry, and then press ENTER.
5. In the right pane, right-click PromptForCredentials, and then click Modify.
6. In the Edit DWORD Value dialog box, and then type one of the following values in the Value data dialog box:
   
   
   Value	Description
   0	Cached credentials are used.
   1	Cached credentials cannot be used. You are always prompted for logon credentials.

7. Click OK.