For a long time I've been dismissing and ignoring this popup, which is easy since it only appears at boot (or logon) which is once every few months:
But recently I became suspicious after a crash (which killed my multi-month uptime) and opened the main dialog, to find the whole thing had been disabled:
Most of the user interface (including tabs) is disabled - the only things that work are the Help menu and the blue hyperlink.
I want to know if I am the only person (or one of a small few) who has seen this dialog!
It is certainly a planned action by Microsoft (to persuade us to upgrade Windows), but I wonder if some malware triggered it early as a sneaky way of disabling MSE. Two things that make me suspicious are that I can't reproduce it in a virtual machine, and even though I first noticed it almost two weeks ago, Google doesn't know the phrase "Microsoft Security Essentials is no longer protecting your PC". (of course that will change when it indexes this question)
There are supposed to be three "end of life stages" for MSE and my main PC is at stage 3, in which MSE stops working altogether, but even though Stage 3 was supposed to begin on July 14, I can only reproduce stage 2 in a virtual machine. (its message is the same as in the popup shown above and nothing is actually disabled)
So has anybody else experienced Stage 3?
Please don't say "stop using Windows XP". While it might be a good idea, it doesn't answer the question.