Windows 8 Action Centre Question

The little Action Centre flag on my taskbar shows a small S. When I click on it it says Scheduled Scan, when I click on that it brings up Windows Defender telling me the scheduled scan completed yesterday at 5am. Exactly what action am I supposed to take to get rid of this alert?

Edit: It is not an S it is a little timer symbol. Confused I am.

Edited by Banger (Thu 19-Dec-13 22:34:54)

The plot thickens. I try a quick scan with defender and it gets stuck on 4 items maybe the schedule scan is also stuck?

The timer symbol just means it is doing maintenance - that could be a variety of things one of which is a defrag.

Seems fixed after a reboot, can now quick scan, and update definitions which were 2 days old according to the update tab. Once the update completed and quick scan everything seems back to normal.