I have created a C# Windows Forms application using .Net 4.5 and referencing Microsoft.Office.Interop.Outlook.dll which is used to access Outlook messages. When it is loaded (but not executing any code) at the same time that Outlook is running, Outlook periodically prompts for credentials even though it is connected to Microsoft Exchange (using Cached Exchange Mode). Supplying credentials (with remember me checked) does not prevent the prompt from re-appearing. The account the application and Outlook is running under does not have local admin rights.
I have tried removing all Generic Credentials via Control Panel-> Credentials Manager, but this does not remove the problem.
Edit: After restarting a number of times to determine whether it was the loading or running of my application that caused the periodic prompting, the problem disappeared. Outlook now runs OK without any periodic prompting while my application runs and and uses the Outlook Interop. Very strange.