This setting is one of those that are really frustrating to find.

Follow these steps to enable email pop-outs in Outlook 2016 settings:

- Go to **File** at the top menu of Outlook 2016

- Select: **Options**

- Then **Mail** tab on the left side menu

- Select section: **Replies and forwards**

- Check-mark option: **Open replies and forwards in a new window**

- Press **OK** button

Screenshot: