I have 4 personal Macs (3 iMacs and 1 MacBook Pro), all running Teamviewer v12.0.78517, but this is not about a particular version. Rather, my question is this: it seems that the contacts (one for each computer so a total of 4) log in and log out with what seems to be no reason or regularity. How can I decide to either log in or log out any contact at any given time? I transfer files and that cannot be done when the contact is not logged in. I know that I can transfer files when I have remote controlled the computers. I cannot find any preference that specifically talks about this subject. Suggestions?