I have tried all that you suggested and it didn't make any difference. After uninstalling Avast, I have even gone into the regsitry and removed every reference to Avast and alwil that 'search' could find, before reinstalling it again. What is odd is that I have Avast Anti-Virus on my wife's computer also. I have looked in the registry on both machines to try to see an Avast add-in listed under Outlook\Addins. There doesn't seem to be one listed anywhere that I could find, even on my wife's machine when the Avast add-in was showing up in Outlook. The Outlook/Exchange provider was working on her machine - for a while. I didn't do anything to disable or remove it, it just disappeared. Now the Outlook/Exchange provider control on her machine says that it is waiting for a process to start, even when Outlook is open. When it was working and the add-in was showing up in Outlook, right as Outlook was starting, an Avast screen would flash up for a second or two, and then Outlook would go ahead and open and the Avast screen would disappear. When the add-in isn't showing up in Outlook, no Avast screen flashes up. This is obviously what you would expect, however. Both machines are running Vista Ultimate. Is there an .ECF file that can be saved to the Office10/Addins directory so that the Avast add-in will show up in Outlook and stay there? There wasn't one in that directory on her machine, even when the Avast add-in was showing up in the Outlook add-ins. I am at a loss.