@Marcos: That is interesting. I've been keeping an eye on the compatibility chart at hxxp://support.eset.com/kb2138/and it still says there are no ESET products with Outlook 2016 support. I've only got 4 machines, but I'd consider upgrading to a 5 machine license to get support for Office 2016.
@zedgama3: Exactly the reason I reverted to Office 2013. I had two computers, one running 2013 and a new one running 2016 and the 2016 one would not flag up malware seen by the 2013 machine.