Windows 7: updates notification

Win 7 Home Premium, IE9.
Security program : MSE

My Windows Updates is set at manual.



For the past few days, some thing strange happened.....
I received notification for an update > opened my Windows Update, and it said it is fully updated.
Then I clicked open Check for Updates, sure enough there was an optional update. So I installed it.
That happened at least 3 times.
All the optional updates are for Definition update for Microsoft Security Essentials.
Can some one explain this issue ?

Another question ......
Why are those definition updates categorized as " optional " ???

Thank you.

Hello!

I shall answer that question.

There is actually a very specific reason. Say that you have MSE set to auto-install updates at 14:00 every day (actually set by auto scan at 14:00, and update before a scan). Say that Microsoft happen to release an update at 8:00, and you happen to check Windows Update at 10:00.

The MSE definition updates will be shown, but are marked as optional because if ignored they will be installed within 24 hours (at 14:00 in this example)

I know they are a bit disconcerting, I know how you feel, but they will auto-install given time.

Richard

Thank you.

Thanks a lot, and glad to have been of assistance! What about "I received notification for an update > opened my Windows Update, and it said it is fully updated.". I am afraid to say that I don't know the exact answer to that. Do you want me to see if somebody else does?

Thanks a lot!

It is not urgent, but yes, I'd like to know why Windows Update window said there was no update for me when there was an optional update waiting.