Egnyte provides the ability to "Save to Egnyte" from an email in (desktop) Outlook 2016. The functionality is achieved by opening the email in a separate window and then selecting the "Save to Egnyte" button found on the "Message" tab.
If the user uses "Preview," however, the "Save to Egnyte" button is not available because the "Home (Mail)" tab is shown. To save to Egnyte, the user has to click "Save as," find the directory, etc.
My suggestion is to add the "Save to Egnyte" button to both the "Home (Mail)" and "Attachments" tabs to make it easier to use this feature.