Good evening! I want to share a solution to the problem (Sori, if it has already been discussed), with which I met after the recovery of a backup when you return to the desired firmware (I was pre-fully wipe). So, after starting the system, the graphic key stopped approaching (if the password had stood, then the password did not match) and the problem solving the system only gives a reset to the factory settings through the recovery. But the solution was simple, you need to delete the necessary file manager in DATA through the file manager in TWRP =>system =>gatekeeper.pattern.key (unlock) or gatekeeper.password.key (password).
After starting the system to set a new key or password, reboot, and everything is normal.
Thanks for attention :)
MIUI9 android6