In Outlook 365 (installed on my Win 8.1 Pro laptop), many emails are displayed in a narrow centered column instead of filling the panel width. This is both in preview mode and when the email is opened. It mainly happens for bulk emails e.g. sent by LinkedIn, AWS, blogs and so on. Often I actually need to open these emails in a browser in order to be able to read them.

I have noticed other people reporting this issue in this forum but with no solution posted from Microsoft. I have tried running OffCAT but it doesn't pick up the problem.

I tried uploading screenshots but your forum doesn't allow me to do that.

You are not alone on this issue. I've seen some users in this forum have same problem. Seems no good solution so far.