I had changed a password for an account titled student with no password by doing this in single user mode,
fsck -fy mount -uw / passwd student
The password now is student, but when I try to change back the password to no password again, it says “no changed added”. How do I restore it back to no password?
From this post.
passwdcommand rejects the idea that you can have a 0 length password.
dsclwhich is more accepting of the notion that the password is nothing.
dscl . -passwd /Users/foo
You can press enter to make the new password blank and then may get an error and have to enter the old password if you are not root but once you authenticate (or are root already) the blank password will be written.