I want to share everything on an iMac with other Macs using File Sharing, though I am concerned with the possibility of someone else getting into the iMac with the sharing turned on. I just checked the settings and it shows that only one user has access to read & write to the Mac and Everyone else has No Access. Well, I just got a new Mac and it is not on this list, though it lets me right into my Mac. Is this because it is logged into the same iCloud account? Is the user based on the iCloud account and not the Mac itself? 1. What extra security, if any, can I take to protect the Mac from others? Thanks.