There is no official setting to hide of the “Favorites” folder section from the sidebar on outlook.live.com.
- Note there is a setting one for the desktop Outlook app to hide Favorites: View > Folder Pane > Favorites (uncheck)
However, hiding the Favorites folder section on the online version may be quickly and easily accomplished by simply removing all nested sub folders from the Favorites folder section.
To remove a sub folder from the Favorites folder section simply right mouse click on any sub folder and select “Remove from Favorites“.
Once all sub folders have been removed the Favorites folder section the entire Favorites section should automatically be hidden.
As always, I welcome your thoughts, questions or suggestions on my article on how to remove or hide the Favorites folder from the Outlook.Live.com sidebar.
Let me know if you found any errors within my article or if I may further assist you by answering any additional questions you may have.