The Clutter option is a new Exchange Online feature, which was created to help Office…
Clutter is an Exchange Online feature that was created for optimizing the management of the user mailbox by relocating not important or non-relevant E-mail message to Clutter folder
In a case that you want to disable the option of Clutter, you can use the OWA web interface for disabling the Clutter option.
Notice that when you disable the Clutter option, a new email message will not be “moved” to the Clutter folder but, even after you have disabled the Clutter option, mail that was already “moved” to the Clutter folder will continue to stay in the Clutter folder.
In case that you want to remove all traces to the Clutter option, you will need to move all of the mail items back to the inbox folder and then, manually deleted the Clutter folder
How to Disable to option of Clutter by using OWA client
Login to Office 365 portal and access your mailbox using the mail icon
Choose the setting icon and the Options menu
On the left menu bar, choose the Clutter menu
Choose the option – Don’t separate items identified as clutter
Click on the Save option
Note – in the current time, there is no option for disable the clutter option using the Outlook mail client.
Remove the clutter folder using OWA mail client
The Clutter folder remains in Outlook after you turn off Clutter feature. If you don’t want the folder listed under your Mailbox, it will need to be deleted from Outlook.
First, move the emails from Clutter folder to another folder, and then right-click the Clutter folder and choose Delete