I've been struggling immensely with slow internet speeds everywhere I go with my MacBook. Moreover, when I turn my Macbook on, it completely jams the internet for all other devices as well (connected via wifi and ethernet).
I've been in discussions with Apple at length about the issue for about 4 months and they eventually replaced my laptop.
But, when I had to use another computer at work for Photoshop while I was without my MacBook, the same thing happened! This time, I was using Windows.
I don't even need to have Photoshop running. I now literally just turn the computer on, and the whole internet connection grinds to a halt for everyone. I turn the computer off, perfect internet speeds.
I've searched forums for this, and I can't find anyone else who has experienced something similar.
I need photoshop for my job. I haven't been able to properly work now for 4 months. Any help would be so appreciated.
Have you checked for malware? You can get a free trial of Malwarebytes or Bitdefender if you haven't used them before. While it used to be that Macs never got malware or viruses, that is no longer true.