secret filesharing

My iMac was used by a user who was given the admin password. I am doubting that he installed some program which will automaically send my newly created documents and other files to his machine. I went to the Network Utility and found something "afs-fileserver..." entry which is increasing my doubts. Each time I connect to the internet I hear a lot of sound from the machine and even the browser takes a while to get to normal speed. So is something happening behind the scenes? How do I monitor this and uninstall any such hidden program?

G'day and welcome to the forums.

Not a wise thing to do sharing password. Go into System Preferences > Users & Groups > Password and select Change Password and proceed to change it. Delete your Network, boot the router into the URL address and make a new account, with a different name such as mozhozsworld', security WPA2 Personal, a new 13 digit alphabetical and numerical password, wit'h the odd capitol, and set up Network under 'Automatic', select the new name and enter the password.

Hi mozkhoz

There is almost no reason to give anyone else admin access to OSX unless you completely trust the person.

Most computing tasks can happily be done at the User level. as harryb2448 says, it's best to change everything you can think of network wise.

If you have a cable modem and / or fixed IP, you can ask your service provider to provide a new one as a final precaution.

If you want to verify if the machine is connecting to the internet behind the scenes, you can install an OS X application called " LittleSnitch "
Little Snitch

That will alert you on any attempt to create an outgoing connection.
By using that, you can identify and learn what is legitimate outgoing traffic and what is not.

Cheers ... McBie