We had a customer who’s Outlook keep popping up the following dialog box.
Here is the link we used to understand the issue.
This location uses Vipre Antivirus. We logged onto their server and went into the Vipre console. The customer’s machine appeared up-to-date with the client; however, the definitions were slightly behind. Not by much. We pushed “Definition Upates”, and this resolved the issue right-a-way.
Let us know if this helped you…