Sending, receiving, and organizing email in Outlook.com
Hi @Steven G
First, please check the AI answer
Since the wider margins affect both old and new messages, while the reply editor still appears normal, the original formatting of your emails has most likely not changed. This sounds more like a rendering issue in Outlook.com.
Please try opening Outlook.com in an InPrivate or Incognito window. If the messages display normally there, a browser extension or stored site data may be interfering with the reading view. You can then disable extensions one at a time, especially ad blockers or page-formatting extensions, and clear the site data specifically for outlook.live.com.
It would also be useful to test the mailbox in a different browser. If the same margins appear in multiple browsers and devices, the change may be coming from Outlook.com itself rather than from your browser settings.