I have the same issue after upgrading to Parallels Desktop 11 (Guest OS Windows 8.1. Pro), MacBook Air (13-inch, Mid 2013), OS X El Capitan 10.11.
Option "Use All Displays in Full Screen" is checked, but after restarting Windows got a request to change password, which does not work.
Unfortunatelly I can't even resolve this problem with standard commands in Terminal "prlctl list --all; prlctl set UUID --userpasswd nameassword" - which worked well before, now the answer is : "The command is available only in Parallels Desktop for Mac Pro or Business Edition".
Instead of correcting Windows Full Screen issue don't have Windows OS at all.
Moreover, my question to Support (ticket # 2181649 from Last Friday) was not read by anybody from Support yet.
My question via mail to support@support.parallels.com from 08.10.2015 (five days already) still without answer.
I have code for phone support, by don't see any non-American phone number to call for support.
I'm really very upset.
UPD. to reset password under PD11 (not PRO) - try http://kb.parallels.com/ru/117557
Last edited: Oct 13, 2015