outlook error message "not a valid Office add-in"

Whenever I open Outlook I get ths message
'C:\WINDOWS\Application Data\Microsoft\AddIns\' is not a valid Office
add-in.
If I click OK it usually works normal, but yesterday it started not bringing
anything up on the screen after I clicked OK. The taskbar at the bottom
would show that Outlook was open, but I couldn't see the application. Now
all the sudden it started working again. What can I do to keep this from happening every time.
Thanks
Don

 

Searching on the Microsoft Knowledge base I come up with one or two examples-will only post one-are you getting an actual file name with your error message as you will oberve in this example:

Valid Office Add-In

Are there any more details you can supply?

HumBug