I don't know if it helps to make MS aware there is a problem if there is a lot of us... but I can always try and add my bit too, no?
I have more or less the same problem.
I reinstalled an older Vista laptop with W8 and then upgraded to 8.1 when that became available.
This is on a an Acer laptop.
As I had managed not to give my hotmail password with the first install, I don't know if there was a problem. Num lock was on when I got to Start. With 8.1, no escape, I had to have a login. And indeed, as described above, num lock was off when I had to type
my password - with the difference that it was/is not a sometime thing - it is always.
On that same laptop when it was still running with Vista, I had a similar problem when I decided one day to define a Windows password. And though I was sure I was typing it correctly, I never managed to access Vista with it and after unsuccesfully trying some
software to find and eliminate the password I had to reinstall Vista... So I am not so sure if it is a Windows problem or something of the Acer configuration that still sticks around... It was a long time later when I realized what had happened when I was
trying to help a friend with the same problem, also on an Acer - with Win7.
I checked in the registry and that setting is correct to turn on the num lock after logon. And I don't know, of course, if that works as I have to turn it on manually to get past the logon in the first place...
So my problem looks like a variation of the same theme and it might help to shed a light on why it happens, maybe? If the prbl is on MS side or a laptop problem?
Grts
Nil