How do I reset my forgotten Mac Book Pro login password ?

Question

The "help" on my MacBook Pro insists I can change my forgotten login password by using my apple Id and password, by simply hitting the arrow beside the login password box. It appears after a failed attempt to enter your password at Login, however the drop down menu does not appear. The whole box shakes and that is all. In other places such as security and privacy all attempts are blocked , because I am asked to enter my (forgotten) password.
Please advise, kind apple lovers.
x

Answer 1

If the user account is associated with an Apple ID, and you know that account password, the Apple ID can be used to reset your user account password.
Otherwise, boot into Recovery by holding down the key combination command-R at startup. Release the keys when you see a gray screen with a spinning dial.
When the OS X Utilities screen appears, select Utilities ▹ Terminal from the menu bar.
In the Terminal window, type this:
resetpassword
That's one word with no spaces. Then press return. A Reset Password window opens.
Select your boot volume if not already selected.
Select your username from the menu labeled Select the user account if not already selected.
Follow the prompts to reset the password. It's safest to choose a password that includes only the characters a-z, A-Z, and 0-9.
Select  ▹ Restart from the menu bar.
You should now be able to log in with the new password, but you won't be able to unlock the Keychain. If you've forgotten the Keychain password (which is ordinarily the same as your login password), there's no way to recover it. You’ll need to reset your keychain in the preferences of the Keychain Access application.