I haven't used Outlook in ages, but I would be so surprised if it
couldn't. By the way, it would help to also mention what version of
Outlook you are using. I also don't know if you are using the classic
menu, or the ribbon toolbar. Anyway I would start with the view and look
for sorting options. If that fails, next see if you can create a
read/unread column. Once created you can click on it and sort by
read/unread. Those are what I would try first anyway.