Another Wi-Fi issue

[seveej]

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)

 

[JohnDS]

If the Mac is still under warranty, I would take it into a Genius Bar. Sounds like it might be a hardware problem.

 

[vexorg]

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.

 

[seveej]

If the Mac is still under warranty, I would take it into a Genius Bar. Sounds like it might be a hardware problem.

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'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.

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,