Close all applications and shut down the computer , press command , R and power key simultaneously , release only power key and keep on holding command and R key until apple logo appears , the bar starts loading let it be completed .
Select the language as English , go to utilities on top menu bar > Utilities > Terminal execute a command resetpassword and click on enter key .
Window appears , select your admin name it will prompt to enter Apple ID and password .
Once you enter the credentials , two options will be shown ( a ) previous ( b ) next , click on next . Some fields will appear . New password ………. Verify password ………. Password hint ………. Enter your new password in two empty fields and keep password hint as empty ( optional ) . It will again prompt two options ( a ) previous ( b ) next Click on next .
Then it will prompt to restart the computer , so after restarting the machine .Pop - up will appear
The system was unable to unlock your login keychain , if you remember your old password you can update the keychain password .
If you do not remember your old password , you can create a new login keychain or choose to leave the login keychain using a different password .
Would you like to update the password , create a new keychain , or continue the login ?
A window will appear on your desktop .
( a ) continue login .
( b) create new keychain .
( c ) update keychain password .
Click on update keychain password , then log out from your computer .
When you again login in the fields enter your “ admin name “ and “ old admin password “ , so that new password will be updated with login keychain .
Hence , the admin password is changed with the help of “ Recovery mode “ only .