Lots of hard work was put into the latest Mac version of Microsoft Office, and it shows. However, when you check the general preferences again, this option is not enabled.
In Outlook Preferences, under General, you enable the Make Outlook the default application for e-mail, calendar, and contacts option. In Microsoft Outlook 2016 for Mac running on Mac OS X Yosemite (10.10) or later versions, you cannot set Outlook as the default application. You’ll have Office applications on your Mac or PC, apps on tablets and smartphones for when you're on the go, and Office Online on the web for everywhere in between. Office 365 customers get the new Office for Mac first. Microsoft Office For Mac Os X Yosemite 10.10.5.Perhaps this is a good spot to remind everyone that Excel originated on the Mac! Office has long been the productivity suite of choice in the Windows world, and it’s also been a favorite for even longer on the Macintosh side.