VSTO Add-Ins becoming acting inactive while computer is locked

[Carl]

I have developed a VSTO Add-In that reroutes incoming email into a folders
based on the new email's subject line, body, etc. The appropriate events
seem to fire without a problem while I am actively working on my machine, but
when I lock the workstation overnight, the Add-In stops managing the email
properly.

Can anyone offer some insight into this issue of mine?

Thanks