I did a search before making this report. Couldn't find it.
When I go to logging in, it either won't save the PW I had, or it will show that I did save the PW and I go to log in and it won't let me, saying that the PW is wrong. So for the past few days I been testing this.
What I found is that even when I know the PW is right, and I get this random error, I just close the popup error message it gives me about checking my CAPS LOCK etc etc, and I don't change anything, I close the popup error message and instead of my changing / retyping the PW, I just click login once more and it lets me in just fine.
So this is a random bug in latest Full Release Sing.
Windows 7 x64
i7 6-Core @ 3.3 Gighertz / Core
64 Gigs System Ram
GTX 980 w / 4 Gigs Ram