[jamestnz]

I just got through researching this issue for a client. Apparently it is at least somewhat common, and appears to be caused by RF interference/noise radiating from USB 3.0 ports and cables, which stomps over 2.4 GHz band.

Popular solutions seem to involve applying custom shielding to dongles/cables/adaptors, trying different models of these, or experimenting with their physical proximity and layout. Sigh.

Discussion, including a link to an Intel whitepaper on the topic, here: https://apple.stackexchange.com/questions/329970/usb-c-dongl...

[FabHK]

Yes. Best fix (when possible): switch to 5 GHz WiFi.

When the MBP with USB-C first came out in late 2016, I noticed this issue and documented it and brought the machine to Apple, and they offered to exchange the motherboard. However, work and travel prevented me from bringing the machine in, and when I brought it to the shop next time to have it fixed months later they said it’s a known issue that can’t be fixed. Use WiFi, plug in an external HD - choose one.

Edit to add: I even asked HN, but it didn’t get answers:

https://news.ycombinator.com/item?id=13494910

[bambataa]

Thanks for the info (and the child comment). I'm really glad I spent so much money on this laptop.