In the September 2015 update of "Outlook on the web", users have noticed that the default reply setting has changed from "reply" to "reply all". This could cause users to inadvertently reply to all users in an email thread when they intended to reply to the sender.
When viewing a message within your reading pane or separate window, you will see the following button:
If you click on the button, the default action is to perform a "reply all".
To reply or forward the message, you must click on the down arrow next to this action and select the desired action:
To change Outlook on the web's default setting back to "Reply":
- Click the Settings gear icon and then click Mail under "Your app settings".
- If not already expanded, click to expand the "Mail" section.
- Expand the "Automatic processing" section.
- Click Reply settings.
- Select the "Reply" setting and click Save.
- Return to your Outlook screen. The default action will now be Reply.