I have an issue, I bought my Mac second hand and I am not the Administrator. I've been having weird thing happen on my computer, shutting down, restarting, and it seems to me I've been hacked.

This morning I was Google plus and it was taking ages to load, so I switched my browser to Google Chrome and it normally comes up with my email to log in, but this time I looked at it and it was the old owner of the computer. I looked at the certificate in keychain and it was September last year. The only way he could have logged in was by hijacking my computer, because I've had it for 3 years.

Which comes to Remote Desktop: I looked at the software and it's viable he's still logged into my computer via still being an administrator. I changed all the screen sharing permissions, but then they would mysteriously change back to screen sharing... I really need help with this... what do I do.

I changed all my passwords, and am using Little Snitch, to see what's going on, but I can't remove his admin account from my computer?

  • 2
    reinstall the OS from scratch - you cannpt use a computer without an admin accounbt – Mark Jul 5 '17 at 9:19
  • how do I do this? sorry im only learning command-R on start up ?? – Jaya Sri-Radhe Jul 5 '17 at 9:42
  • @JayaSri-Radhe Yes start the Mac while holding Command-R, then go to the top menu and erase the hard drive with disk utility (GUID partition - Mac os extended journaled), then quit disk utility and select "install a new copy of os x". – Matteo Jul 5 '17 at 10:22
  • thankyou.... I did all that and still couldn't install. I have a bootable usb with Sierra on it, but my trackpad clicker is defunct. I was using control fn f2 for navigation, got into disk utility, and my bootable usb was no where to be found. I might try it again, but it's frustrating the sh^t out of me.... any advice from here would be great. Thanks in advance – Jaya Sri-Radhe Jul 5 '17 at 17:54

Restart your computer. Press the Command and R keys at the same time when the grey screen appears and hold them until you see the Apple logo.

Click the Utilities tab in the top menu bar, select Terminal, type resetpassword and press Enter.

Close terminal window, behind it is the Password Reset utility.

Select the user account you want to reset, enter a new password or leave it blank and click Save.

Restart the computer.

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