I'm trying to perform a 25GB file transfer between my MacBook Air and Mac mini, both running Sierra. The files are on the MBA and I'm opening a finder window, navigating to my desktop folder on the mini as a shared device and then simply dragging and dropping the files. The first 30MB transfer instantly then it just grinds to a halt and the transfer time quickly goes from 45 minutes to 2 days. I've tried different combinations of SMB and AFP but to no avail. The MBA is connected to my wifi network and the mini is connected to my Airport Extreme via ethernet. Anybody else experienced similar issue?