A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
I do not use Skype, Outlook, Firefox or Google Chrome, all of which are some of the apparent culprits with this problem. In my case the culprit is Zone Alarm Pro (version 11.0.768.000), issued in July 2013. No problems with Zone Alarm Pro before that. When I turn it off my Excel problem does not happen. Turn it back on and the annoying message reappears. Hope this helps some of you.