Performed an in-place upgrade from El-Cap to Sierra on 2015 retina macbook pro. Since then 2 of 3 accounts experience extreme long delays during log on. After entering the users password it displays a spinning circle for between 3 and 6 minutes. Finally it will show the desktop and the machine works as expected. One of the 2 accounts with this problem existed under El-Cap, the other created today as a test. Open to any suggestions because the typical troubleshooting hasn't helped.