I have three Macs on my home network. A white Macbook, a 2015 Macbook Pro and a 2015 iMac. So, I sit at my iMac and can see the Macbook and Macbook Pro in the sidebar of any Finder window and connect to both as I have 'Screen Sharing', 'File Sharing' and 'Remote Login' ticked in 'Sharing in 'System preferences'. But while I can drag and drop files to and from the old white Macbook with this arrangement while Screen Sharing I can only drag files from the 2015 Macbook Pro. I cannot send or drag files to it. The only difference between the set-ups is that the the old white Macbook is connected to my router via an Ethernet cable while my 2015 Macbook Pro is connected to the router wirelessly. Any ideas?