Here's a user issue that was escalated to me: the user had a password worked fine when linking to mail on his smartphone, but failed when logging into Windows. I met with him face to face to sort it out.
And it's just like he says. He put it in his phone and it worked, and could not log into Windows.
I asked him to tell me his password so I could try it. It's "ABC<>1", without the quotes.
And Window logs in perfectly for me. I had him try again and watched his fingers. He was typing "CapsLock a b c , . CapsLock 1" while I had typed "Shift-A Shift-B Shift-C Shift-, Shift-. 1". The damn CapsLock key doesn't Cap Lock special characters.
We cursed Microsoft and all was well. ;-)