WiFi issues with new MBP on 2.4GHz

Discussion in 'Mac Basics and Help' started by needlz, Sep 5, 2017.

  1. needlz, Sep 5, 2017
    Last edited: Sep 5, 2017

    needlz macrumors member

    May 14, 2008
    Zurich, Switzerland
    I've a new MBP, which connected fine to all WiFis until a few weeks ago. Does anyone know what I can try to resolve the issue?

    The error says "The Wi-Fi network ... could not be joined.
    This is what I've done so far:

    - Tested multiple WiFis on 2.4Ghz (5Ghz works fine)
    - Checked if passwords are correct (works by joining with an iPhone)
    - Reset PRAM and SMC
    - Just for the sake of it, changed MAC address (but there is no MAC filtering enabled..)
    - Created a new location and used the assistant to connect (here the error said "password is incorrect").

    I'm running macOS Sierra 10.12.6. Appreciate any help.
  2. Marcopolo53 macrumors regular

    Oct 21, 2016
  3. chown33 macrumors 604

    Aug 9, 2009
    Start with Wireless Diagnostics. The actions needed to run it are under the "Analyze your wireless environment" heading:

    The Utilities window is used for the following, not the Diagnostics window. See the heading "Use other diagnostics utilities".

    1. Do a Scan (search for it on the web page), and post the RSSI for the networks visible. Signal strength, interference, other networks, etc. can have a large effect.

    2. As suggested above, make sure Caps Lock isn't enabled. Then delete the saved network and enter the info again.

    3. Run the Performance graph when connected (search for it on the web page). Quality and Signal give info on signal quality, which is affected by signal strength, interference, distance, etc.
  4. kohlson macrumors 68000

    Apr 23, 2010
    The error message suggests that it's a signal strength issue. Following the above will provide good insight.
    - Can you connect to other 2.4 GHz networks?
    - Are all the signal bars in menu bar at the top showing?
    - Are you far away from the router, with metal/stone objects in the way?
  5. imaccooper macrumors 6502


    May 29, 2014
    North Carolina
    A few things to try...

    1. Go into wireless settings and delete the network from saved and then try to reconnect. If encountered so many weird things with old saved networks.

    2. Move your router around to see if there is interference nearby (Bluetooth, sound systems, microwaves, pretty much anything). Since 5ghz works fine, physical objects are likely not the problem because they would affect 5 more than 2.4, but things mentioned above will affect 2.4 more than 5 especially microwaves.

    3. Delete network as mentioned above then before reconnecting, put your Mac right beside the unit within a foot or so and try to reconnect. If this works then your antenna is likely the problem.

    4. Unlikely to be the problem, but make sure you are getting a proper IP address and subnet for your network. I've had this happen before and ended up having to set a manual ip address with dhcp. Very annoying.
  6. Fishrrman macrumors P6


    Feb 20, 2009
    Just wondering -- do you have anything plugged into the USB-c ports while you're trying to establish the connection?

    Why I asked:
    Could be interference from USB3/USB-c ...
  7. needlz thread starter macrumors member

    May 14, 2008
    Zurich, Switzerland
    Thanks for all the replies! I've doubled-checked the passwords (e.g. no CAPS LOCK), no USB* devices are plugged in, deleted all network settings (and also logged in with the "guest" account). I'm slowly beginning to think that it's a hardware issue and will check with a local Apple Store.
  8. woodini, Sep 14, 2017
    Last edited: Sep 14, 2017

    woodini macrumors newbie


    Sep 14, 2017
    I'm having the same issues yesterday on a 3 week old 12" Macbook. Previously I had removed all of the SSIDs from the Wireless preferences from stations I no longer connect to. Thankfully I didn't remove my home ones or my iPhone tether. It won't connect to anything else now. I've done a permissions fix, checked the keychain, tried connecting from the guest account etc. Very frustrating.

    Edit: I popped into an Apple Store this morning and chatted with a member of staff who advised I remove the WiFi adaptor entirely from my Network location, then re-add it. That seems to have worked.
  9. needlz thread starter macrumors member

    May 14, 2008
    Zurich, Switzerland
    Unfortunately that didn't to the trick for me. I might give updating to High Sierra a try this week, before bringing it to the Apple Store.
  10. woodini macrumors newbie


    Sep 14, 2017
    I ran into a similar problem with a client of mine last Friday and was able to get around it by manually adding the SSID and security details back in by using the '+' option in Network Preferences > WiFi > Advanced > Preferred Networks.

    Might be worth a go?
  11. needlz thread starter macrumors member

    May 14, 2008
    Zurich, Switzerland
    Thanks - I just tried a final test with booting via Recovery Disk (so no installed configurations/drivers are loaded) and trying to connect from there - still showing the same error. I guess I'll have to find time for an Apple Store visit now..
  12. nzwinmac macrumors newbie

    Mar 19, 2019
    I just spent half a day debugging issues with WiFi on my new MacBook Pro. Same problem as described in this thread. Issues only on 2.4GHz. Well, apparently USB3.0 is to blame, as it creates interference on 2.4GHz. Disconnect all your USB devices from your Mac to confirm that this is the same issue you're facing.

    OK fine, I understand, but why does my Android phone have no issues when sitting right next to the Mac? That makes me think that this issue is due to something that was badly designed by Apple. Very disappointing indeed!

    see more:

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11 September 5, 2017