Had the problem that my Outlook Code for accessing the opened calenders in Outlook 2010 sent me a mysterious error message (registry / installation problem in outlook. Reinstallation necessary).
After posting this information in the OutlookCode Forum (really good, really experienced people). My first stop in problems.
The problem was that my Application reference was created newly
Microsoft.Office.Interop.Outlook.Application outlookApp = new Microsoft.Office.Interop.Outlook.Application();
After changing the code like below
Microsoft.Office.Interop.Outlook.Application outlookApp = Globals.ThisAddIn.Application;
The code went through without problems…. stupid error… 😦