New problem with my "new" computer. I had previously had problems with Migration Assistant. My problem today is when I try to unlock my security/privacy system preference after putting in my password, which is blank it continues to stay locked. I can unlock the accounts preference with no problem. Because of this, I can't put my firewall on and I can only open things to install from the app store.
Barb Phillips 15" MacBook Pro OS 10.10.5 17" MacBookPro OS10.6.8
Try using Disk Utility in Recovery Mode (you described doing that in a post in another thread) to change your password from blank to something with characters. I seem to recall that more recent versions of OS X do not like no characters as a password.
On a Mac since 1984. Currently: 27" iMacs, Macbook Air, macOS 10.14.x,; iPhones, iPods and iPads galore!