I've been struggling to get files between two Macs — Mac File Sharing — and it's been very unMac-like.
I followed the web pages and YouTube instructions to no avail. I have everything set up correctly, but only the machine name is recognized, not the folders and files. "No Connection." What follows is the desperation method.
Both machines need to be on the same network. 192.168.2.x Home Network in my case.
— Sending Machine
Know the sending machine IP address. 192.168.2.103
Apple > System Preferences > Internet > Network > IP Address.
Make or confirm that there is one Shared folder and that it's Read & Write by everybody. This is the "mailbox" folder.
Apple > System Preferences > Internet > Sharing > [X] File Sharing > Options > Share using AFP > Done.
Know the current user and password.
— Destination Machine
No special network setup needed past a connection to a common router or switch and a similar IP number. 192.168.2.5. If you can watch YouTube, that's all you need.
Go > Connect To Server > afp://192.168.2.103 > Connect.
Login as the Sending user > Select the shared folder > Drag/Transfer files.
That's Apple File Protocol. We're performing a "raw," direct IP connection around the fancy AppleShare protocols.
The system mounts the far shared folder as a "drive" on your desktop. It's bidirectional if you set the Sending sharing right. You can send or receive files.
Kill the connection by Right-Click or Control-Click unmounting the drive. Turn off File Sharing on the Sending Mac. You didn't need File Sharing on the Destination Mac.
Eventually, I'll figure out why regular Mac File Sharing doesn't work. Enjoy.