Clutter is an email sorting feature built into Office 365. This feature analyzes your habits and automatically moves low priority messages out of your Inbox so you can focus on important email. These low priority messages are moved into a folder called Clutter.
- To disable Clutter, open Outlook on the web (check out this article if you don't know how).
- On the navigation bar, go to Settings (the gear icon) > Options > Mail > Automatic Processing > Clutter.
- Depending on which version of Outlook you have, you'll need to unselect Separate items identified as clutter or select Don't separate items identified as Clutter, then click Save.
The Clutter folder will remain in Outlook even if you disable this feature.