PLEASE HELP! can't reset password of 'first user'

[nirmal3913]

hey guys need some help please.
I am very new Mac user.
Bought one used iMac late 2012 running on macOS Sierra
I found out that previous owner have "First User" account . He says he don't know password as he never used this Mac. How do I reset password without knowing the old password for First User ???
I can't seem to install some apps as its asking me for password to proceed.
Please help me

 

[Rok73]

Wait, so this Mac's not stolen?

 

[FreakinEurekan]

Follow http://support.apple.com/kb/HT204904 to reset it to "Factory" condition, which will put whatever OS on it that are with it originally (probably Mountain Lion). Then, you can install macOS Sierra using your own Apple ID.

 

[DeltaMac]

One method for resetting a user password:
Restart while holding Command-R
You will boot to the recovery system. Choose Terminal from the menus.
Type: resetpassword, then press enter. You will see the resetpassword window.
Choose your hard drive, then the user name (from your post, probably First User)
Then, type in a new password, retype to verify the new password, then click Save.
Quit resetpassword app, then restart your iMac. You will boot to a login window. Type in your new password, and you should be able to use that from now on.

HOWEVER - I agree that you should erase the hard drive, and reinstall macOS to the newly-erased drive (you don't know what else the previous owner did, as it would have originally shipped with Mountain Lion, and _someone else_ was using it, and had upgraded it to the current Sierra. What _else_ happened to the software (you don't know! )
Erase the hard drive, setup as a new user, then upgrade to Sierra (you won't need to try to figure out what the password is, because it is a fresh install, and YOU did it!

 

[nirmal3913]

you are such a LEGEND!!!!! Thanks heaps for your time. I have reset the password, however still finding it bit complicated to reinstall OS.
Thanks for replying guys.

One method for resetting a user password:
Restart while holding Command-R
You will boot to the recovery system. Choose Terminal from the menus.
Type: resetpassword, then press enter. You will see the resetpassword window.
Choose your hard drive, then the user name (from your post, probably First User)
Then, type in a new password, retype to verify the new password, then click Save.
Quit resetpassword app, then restart your iMac. You will boot to a login window. Type in your new password, and you should be able to use that from now on.

HOWEVER - I agree that you should erase the hard drive, and reinstall macOS to the newly-erased drive (you don't know what else the previous owner did, as it would have originally shipped with Mountain Lion, and _someone else_ was using it, and had upgraded it to the current Sierra. What _else_ happened to the software (you don't know! )
Erase the hard drive, setup as a new user, then upgrade to Sierra (you won't need to try to figure out what the password is, because it is a fresh install, and YOU did it!