Where do I start, the Outlook app on Mac is so limited. There are a ton of things that you have to use the online version just to perform or configure. If you're used to Outlook on PC and you switch to a Mac, it's even more frustrating. I wanted to have a group of contacts that I can easily send emails to on a regular basis and figuring this out on Mac was so darn hard. I created a 'Group' thinking this was the right thing to do only to find out that there is a difference (on PC) between 'Groups' and 'Contact Groups'. After Googling and racking my brain, I find out that 'Contact Groups' are known as 'Contact Lists' on Mac. If you create the contact list (which you have to alter a setting in preferences just to have that option), you can't see a list of your contact lists unless you use the web browser version. If you maximize the window, you can't create a new email or pop out an email into an actual new window. It'll show up as an immovable pop up that covers the main window. When trying to route my Outlook mail through the Apple Mail App on my iPad, there's a bug that won't allow me to sign in to my Microsoft account (I'm able to do it on my iPhone) thereby not allowing me and of course it is impossible for me to get in contact with some type of customer support. And there are so many more examples. Overall, they're not spending enough energy into optimizing the Outlook for Mac app, the UI can be quite overwhelming, they try to mimic PC functionality in ways that don't work for the Mac context, and good luck trying to get in contact with customer support. If you are a Mac user and aren't required to use Outlook...RUN! Use something else.