I have a normal windows forms program (Not VSTO) which deploys using click once. The issue is that loads of user are having problems with random errors generally stating (fr
Outlook Redemption (Redemption.dll) and Background Threading do not mix.
Similar to your situation, we were logging into the Exchange Server using a background thread.
This lead to intermittent errors of Redemption not being able to log into Exchange.
Also, one of my colleagues had put an Email Pop call in a background thread and, again, sometimes it would work and sometimes it would not.
When using Redemption, always let the main UI thread handle it's operations.
Redemption does not really lock up the application as there are really no long running processes when popping an email, adding an appointment or even hooking into the Email Sent Redemption event to handle logging of information sent via email, etc.