After updating to Sierra, Mac prompts for a password twice

Hello. I've updated the MacBook to Sierra. Previously, it was set El Capitan. During Sierra settings, the system said that I can not use a previous password as it coincides with the password iCLoud. I changed password to a new one. Now when I turn on the MacBook I have to enter the password twice. First, the system asks me my previous password, which stood on El Capitan previously.

Then the system asks me a new password that is on the Sierra.

Tell me what to do? Thanks!