To delete an inbox rule on Office 365 Outlook, please do the following:
Click on the gear icon in the upper right hand side of the window.
- Select Mail under Your app settings. The options menu will appear on the left hand side of the window.
- Under Mail and Automatic processing, select Inbox and sweep rules.
- If you have already had any rules set up, they will appear in the Inbox rules box. Select the rule you want to delete and then select Discard at the top.
- Click Save.
Tip: If you just want to turn the rule off for a while, clear the check box next to the rule.