Another Wi-Fi issue

Discussion in 'OS X Yosemite (10.10)' started by seveej, Mar 19, 2016.

  1. seveej macrumors 6502a

    seveej

    Joined:
    Dec 14, 2009
    Location:
    Helsinki, Finland
    #1
    Disclaimer: I've posted this in the 10.10.subforum, although I am by no means sure it is not a hardware issue.

    Specs: Mid2015 MBPr (15"), 10.10.5

    During the last 18 hours, I've read an immense amount of threads on Wi-Fi -problems in Yosemite, and while I have not found a single matching symptom description, I've tried every tip (NVRAM, SMC, thrashing prefs, new location, command line, new user ... I can't even remember all tricks) - all to no avail.

    • On thursday night, I was working with my Wi-Fi as usual - no problems.
    • Friday noon I opened the machine and now I can not turn Wi-Fi on.

    Scenario1 (menu bar):
    • When opening from restart, the Wi-Fi shows as on (menu bar), but not connected.
    • Once I click the icon, it shows as if it could not find any networks - no surprise there: Yosemite has been quirky, Usually a Turn-off/Turn-in cycle would remedy that.
    • If I now Turn off Wi-Fi it will not turn back on. No feedback, nothing in the console

    Scenario2 (network preferences):
    • If I after restart do not click the menu bar icon, but go via system preferences, it shows as off (although the menu bar icon says otherwise), If I click "on", nothing happens (again).

    Scenario3 (after thrashing prefs):
    • Wi-Fi starts up as normal, shows my network (does not connect automatically as it should)
    • when I select to join the network, the Wi-Fi shuts off, and we're back to where we were.

    The console does not show anything clear-cut. This is all which the console says after a (thrashed prefs) restart:

    Sat Mar 19 09:30:55.127 ***Starting Up***
    Sat Mar 19 09:30:55.488 <airportd[56]> airportdProcessDLILEvent: en0 attached (up)
    Sat Mar 19 09:32:35.339 <kernel> AWDL Sync Enabled 0
    Sat Mar 19 09:32:36.204 <airportd[56]> _handleLinkEvent: WiFi is not powered. Resetting state variables.
    Sat Mar 19 09:32:36.205 <kernel> AWDL Sync Enabled 0

    The fourth line (Wifi is not powered) is what occurs when I try to connect to the network. But this seems to be a spurious message (I've searched, and most situations in which that is reported, are unlike mine)

    Just to pre-empt some questions: Between Wi-Fi working and not working:
    • no updates were installed
    • no software was installed
    • no kernel panics
    • no knocks or drops

    What next?
    I have recent backups (user profile and other folders), so a reinstall would not be out of the question, but to my surprise I can not use the recovery mode for a reinstall, as I do not have an internet connection (even there) - the symptoms are exactly the same.
    (While the diagnostic does not show anything amiss with the hardware, I have some doubts - according to my logic a software problem would not persist in recovery mode.)

    I also have a bootable 10.10 on a USB-stick, but somehow the machine will not start up from that (selected startup disk, but all I get at startup is the "denied" symbol)

    In short, I'm stumped - it's rediculous.

    All help appreciated.


    P.S. notwithstanding the Wi-Fi issue, the machine works - I'm using it even now (bluetooth tethering to iPad for internet access)
     
  2. JohnDS macrumors 65816

    Joined:
    Oct 25, 2015
    #2
    If the Mac is still under warranty, I would take it into a Genius Bar. Sounds like it might be a hardware problem.
     
  3. vexorg macrumors 6502a

    Joined:
    Aug 4, 2009
    #3
    I've got a friend with a intermittent wifi problem, his is out of warranty. When it plays up, he must open and reseat the wifi card. Then it's fine for the next however many months.
     
  4. seveej thread starter macrumors 6502a

    seveej

    Joined:
    Dec 14, 2009
    Location:
    Helsinki, Finland
    #4
    Yes it did sound like a hardware problem. It was not (look below)
    Please, keep in mind though, that Genius Bar's are a feature of an Apple Store, and while there are 112 of them in Europe, the nearest one is (from my current location) 9 hours and 12 minutes away (notwithstanding ferry timetables) and in another country.
    Not that I really would want an Apple store in Helsinki - I very much appreciate the half-dozen independent actors/retailers, half of whom will go out of business if Apple ever opens one of their stores here.

    I had one of those issues in my first Wi-Fi equipped laptops (a PC), the retina MBP though does not have a Wi-Fi card you can detach and reseat...

    So, the actual solution:

    It was the Base Station!

    I started getting highly suspicious when (after one trash prefs, disconnect Wi-Fi manually, restart -cycle), I was able to first see, then successfully connect to my iPhone over WLAN (I had used the iPhone as USB-tetehered, but had set it up to share its internet over Wi-Fi for my son's iPad). It suddenly seemed clear that the MBPr's Wi-Fi was able to form a connection, at least in special circumstances.

    I was able to remedy the specific problem detailed above by resetting the base station (some Zyxel powerline WLAN box). Simple, yet everything but self-evident, considering that the behaviour I was getting pointed to a hardware/OS issue, not a base station-problem.

    So to summarize:

    A base station/AP may be screwed in such a fashion that a mac (yosemite) connecting to it shuts down its Wi-Fi in such a way that starting Wi-Fi up again demands some moderate hacking. Not good.

    RGDS,
     

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