Wifi disables everytime I connect an external HDD

Discussion in 'MacBook Pro' started by davidcafor, Dec 7, 2016.

  1. davidcafor macrumors member

    davidcafor

    Joined:
    Jun 2, 2014
    Location:
    Spain
    #1
    I have noticed that every time I connect an external HDD to my brand new MacBook Pro via usb-c conector the 2.4Ghz wifi shut down.
    Is this a software problem or it's a hardware problem? am I the only one who noticed that?
     
  2. maka344 macrumors 6502a

    maka344

    Joined:
    Nov 4, 2009
    Location:
    London, UK
    #2
    My 2016 (defective screen) mac did that but my replacement doesn't.
     
  3. curmudgeonette macrumors 6502

    Joined:
    Jan 28, 2016
    Location:
    California
    #3
    Hardware problem: It is RF interference between USB3 and Wifi - both using about the same frequency. You need better shielding on the HDD or cable.
     
  4. nebo1ss macrumors 68030

    Joined:
    Jun 2, 2010
    #4
    What? USB 3 emits and RF signal?
     
  5. chabig macrumors 68040

    Joined:
    Sep 6, 2002
    #5
    Cables are antennas. They will emit EM if not properly shielded.
     
  6. davidcafor thread starter macrumors member

    davidcafor

    Joined:
    Jun 2, 2014
    Location:
    Spain
    #6
    So it is a "hardware" problem with the usbc to usb adaptor, or with the macbook pro?
    When I connect an old pen drive it works and with the iPhone connected too.
    It only disables the wifi with the WD usb 3.0 HDD
     
  7. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #7
    There was a video floating around here, showing someone else having the very same issue. They'd plug in a USB device and wifi would cut out.

    I'm not sold its the cables, because if that was the case, it would affect other laptops, but that video (I'll try to dig it up), showed them plugging the same peripheral into different computers and working, only when it was on the new MBP did it cut out
    --- Post Merged, Dec 7, 2016 ---
    Here is is, its a long video, but thankfully you don't have to watch the entire thing to see the problem.

     
  8. maka344 macrumors 6502a

    maka344

    Joined:
    Nov 4, 2009
    Location:
    London, UK
    #8
    My wifi would remain connected with a full signal but wouldn't connect to anything.
     
  9. npreq macrumors member

    npreq

    Joined:
    Nov 23, 2016
    #9
    Wrap the cable and the drive in aluminum foil. If it works, then wrap only the cable or the drive to troubleshoot which one of them causes the interference.
     
  10. xraydoc macrumors 604

    xraydoc

    Joined:
    Oct 9, 2005
    Location:
    192.168.1.1
    #10
    There's strong documentation that USB 3 will interfere with 802.11 2.4GHz wifi. Happens on many machines, not just Macs. High quality shielded cables and hard drive enclosures will help. And consider buying a good quality USB-C cable for the hard drive instead of using a USB-C to USB-A adapter.

    The reason why it may be exacerbated in the new MacBooks is possibly due to positioning of the wifi antennae and/or chips on the motherboard, but I'm not certain that the new Macs are more effected than other machines. Just because the particular Dell model in the video (which I've seen before) isn't effected doesn't mean that it only happens to the new MacBook Pros.

    But, if swapping cables doesn't help, then unfortunately a different model hard drive may be necessary to alleviate the issues.
     
  11. leman macrumors 604

    Joined:
    Oct 14, 2008
    #11
    Its a well documented issue. Your HDD or cable are of poor quality, most likely.

    http://www.intel.com/content/www/us...al-bus/usb3-frequency-interference-paper.html
    --- Post Merged, Dec 7, 2016 ---
    It does affect other laptops. Of course, different laptops have different antenna positioning so the circumstances will be different. But when you google a bit, you will find plenty of XPS and other laptop owners complaining about the very same issue.
     
  12. AlanShutko macrumors 6502a

    Joined:
    Jun 2, 2008
    #12
    It's probably the USB-C to USB-A adapter that has bad shielding.
     
  13. xraydoc macrumors 604

    xraydoc

    Joined:
    Oct 9, 2005
    Location:
    192.168.1.1
    #13
    A good reason to simply replace the whole cable instead of using an adapter.
     
  14. Phil A. Moderator

    Phil A.

    Staff Member

    Joined:
    Apr 2, 2006
    Location:
    Shropshire, UK
    #14
    USB 3 can cause issues with 2.4ghz wifi and it's certainly not an Apple only issue. My router has an option to downgrade the USB port to USB 2 if there are inteference issues and a quick google search showed up this support note from Asus
    The best first option would be to try a different port (so the drive is located elsewhere) followed by better shielded cables (and using a USB-C to whatever cable rather than an adapter) and enclosures
     

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