A few months back, Office 365 introduced a new feature called Clutter. Unlike Junk E-mail, which contains messages that are unsolicited, unwanted, or potentially malicious, the Clutter folder is intended to hold messages that are wanted, but don’t require immediate attention and can safely be ignored.
Office 365 determines which messages are clogging your inbox and moves them to Clutter accordingly. Since Clutter has been in place, some people have felt that it slows down their normal routine or causes them to miss important emails, and have requested to turn the feature off.
Whether or not you want Clutter to move messages is up to you. Clutter can be turned on or off through Outlook Web Access at 365.ucdavis.edu. Toggling Clutter on or off can be done by going to Settings >Options > Mail > Clutter
The Settings Gear can be found in the upper right-hand corner.
If you want to turn off the Clutter feature, choose “Don’t separate items identified as clutter.”