I've solved the problem. It was because of a fault into OnConnection method.

"Mircea Pleteriu" wrote in message
...
Hi,

I have created an Excel COM Add-in with C# .NET with the LoadBehavior set
to
3.
I have installed the add-in and everything worked right for a few days.

Suddenly, I've observed that the add-in is not loaded when I open Excel by
double-clicking an Excel document.
Also, I observed that the LoadBevior (into registry) is automatically
changed from 3 to 2 when the file is double-clicked.

Do you know the reason of this strange behavior?

Thanks,
Mircea