Just bought a macbook pro 13in with touch bar 2018 at powermac, when i plugged my portable hard drive (seagate 2TB) with usb c adapter, my wifi lost its connection but when i remove the portable hard drive, my wifi connection returns. Do anyone here having this same issue? Thanks.
All new Mac laptops with USB-C only ports have this problem. Apple says this is caused by the accessory's inadequate electrical shielding of the cables. Just another way Apple is going cheap and screwing us customers. I have used Windows laptops with USB-C that never experience this issue. Try wrapping the cable and drive itself with aluminium foil. This is what I do to my multi-port hub/dongle that used to intermittently disconnects wifi when connected. It now looks like a freakish embutido with a long appendage but at least wifi doesn't disconnect. Be careful also if you frequently plug in and out through the USB-C ports as they tend to wear rather easily resulting to loose ports and disconnection (sometimes ending in data loss and file system corruption).
It's interference. Switch your connection to a 5ghz wifi if you have one. Otherwise look for usb c hubs that do not cause interference.