Guys...

Have a look at the pic below. It shows part of the Win 10 task bar.
There is a little flag (1) on the MS Mail icon. I got a message from
someone in my live.com.au mail account. I usually use Outlook to
check this mail account. However, having opened the memo in both
Outlook and MS Mail, I cannot clear this flag. There are no other
messages there.

In addition, I have combed and checked and unchecked lots of settings
everywhere - to no avail! Any ideas, please?

Flag Waving in Win 10 MS Mail...
mailflag.jpg