Clutter is a feature of Office 365 that is designed to move low priority messages out of your Inbox and into their own folder, saving you time when you scan for important messages. Clutter looks at what you’ve done in the past to determine the messages you’re most likely to ignore. It then moves those messages to a folder in your Inbox called Clutter.
Clutter is switched on by default.
We recommend that you regularly check your Clutter folder (at least on a weekly basis). If you find an email in your Clutter folder that you’d rather was delivered to your Inbox in future, simply drag the email to your Inbox. The system will know where to deliver the emails from that recipient in the future.
You’ll find other items related to Office 365 here: http://www.st-andrews.ac.uk/itsupport/accounts/o365/
If you require any assistance, please don’t hesitate to contact the IT Service Desk.