Q: OSX Yosemite Wifi issues

Sorry, I've hit an edit bug, so once again, with an edit:

Hey guys, I may have found 1 right strand of forgotten twine on a sister thread:No internet connection after installing yosemite

Especially read the post of csukale

Seems to me some of you even after having performed a clean install of Yosemite, but having migrated the rest from an older system may still have mDNSResponder  launched concurrently with Discoveryd. They will clash!

Quote csukale/ formatting mine:

Hey could you guys do me a favor and check whether or not there's 2 files in your /System/Library/LaunchDaemons folder named mDSNResponder.plist and mDNSResponder_helper.plist?

If you find said files you you then maybe check your log files and see if you have any error messages regarding mDNSResponder in there? mDNSResponder got replaced by discoveryd and I think it therefor should not be launched anymore. For some reason it was still in my LaunchDaemons folder though. I did a clean install on another Mac and those files were not there. Said Mac didn't have any problems with the internet connection.

If you cannot find those files, start a Terminal session and type:

ps aux | grep -i dns

Alternatively, open Activity Monitor and check Process IDs (PID) for either mDNSResponder and Discoveryd.

By either you might detect Discoveryd and mDNS responder running concurrently as well. Do so immediately after a restart, when your internet is still working. Because if one of both processes have crashed/ stalled/ seized, they will probably disappear from the list. Disappearance will be in effect with the first inability to resolve, I think. "Now you see me, now you don't."

If mDNSResponder is still found active in some way on your Yosemite, move said mDSNResponder.plist and mDNSResponder_helper.plist to the desktop and restart. If all is well afterwards, you may thrash both files.

You may also want to post an Etrecheck report, of which we have seen very little in this thread.

And thank you for this forgotten gem, csukale

Hey, square eyes, try and switch your ipV6 on your Mac to link local only in sysprefs> advanced>TCP/IP. Or give it a separate network name. A possibly very good bet here was having a different network name for your 2.4 and your 5 GHz networks. Just a hunch, not reading up on it specifically yet. Good luck!

Your issue I think may be yet another strand of Yosemite network problems than the main illness here.

Just a quick followup. The handoff suggestion did not do it for me. Neither did a clean install without migrating anything! So I went back to Mavericks. Should have done that right away!

I use a 4G modem/hotspot (I'm in Italy) and am having the same connectivity problems-pages loading forever. The only fix I've tried is deleting all my preferred networks and creating a new one. No change. So I thought well if this is just a wifi problem, let me connect the modem via USB and see what happens. No change. So maybe the No internet thread is on to the real issue. Let's hope so .

I am in the same boat trying everything.    I am losing bluetooth even worse than before now and can't use my keyboard or mouse.  I need go to back to Mavericks.  Not sure how but I'll figure it out.  I don't use time machine, but I do back up with iCloud, to my local computer and to a remote drive.

Yosemite has made my experience coming to Apple shake my confidence.

So I've been running with the so called WiFried fix for a few days and as expected I still had disconnections, but as far as I can tell I only had one in 4 days and it was able to recover on its own.

I've also continued investigating this issue. Clearly the issue seems to mostly be triggered by lower signal. Will trying to set channels manually in order to get better throughput, I was able to reproduce the issue by setting my Airport Extreme back from a specific channel to automatic. I suspect that considering the issue for me is mostly on recovering from sleep, it's possible the problem is due to the AP changing channels while the MBA was asleep.

I also noticed that the wifi setting seem to be shared between iOS and Mac OS X. For instance I noticed the MBA would connect to the 2.4Ghz band even though I had never set it explicitly. This is a problem because the 2.4Ghz while stronger is unusable at my house.

UPDATE;

So I went to the Genius Bar and spoke to a very nice guy who was zero help at all.

He didn't acknowledge the 'wifi issue' in Yosemite of course.

He tested the hardware - all passed of course.

Connected to the stores wifi - all ok of course.

Couldn't reproduce the issue in any way.

The only thing left was to reinstall Yosemite completely from their internal copy, which he did.

Upon getting home, fresh out of the box, it couldn't even see my wireless network. (The several Mac's, iPods & iPhone had no trouble).

Tried the neighbours wifi next door, it could see his network after a restart, but couldn't stay connected for more than a few minutes.

So I rang the 90-day support line.

When I explained that it did this fresh out the box, and when it disconnected, the wi-fi 'on' button didn't do anything and only a restart helped, he suggested it may be a hardware issue.

So it's being picked up next week to be checked over.

I don't hold out much hope for this as the hardware was already checked at the store, unless there's a more in-depth check they can do.

All in all, I'm very badly burnt by this whole situation, if all I get back from them is 'we can't find a hardware issue, it's your problem', then a Mavericks install is all that's left. I may even install the demo of Windows 10 on it and see how that goes, which is something I never thought I'd ever do.

No change. So I thought well if this is just a wifi problem, let me connect the modem via USB and see what happens.

And how do you connect a "modem" via USB to gain internet access? Sounds like connecting your gas mains to your water plumbing to get an alternative supplier for drinking water.

Seriously, what exactly were you trying to do?

I am losing bluetooth even worse than before now and can't use my keyboard or mouse.

That is not exactly a Yosemite problem, as I've explained before. Try moving your WiFi over to the 5 GHz band and stop using external USB 3 devices for testing purposes for the moment. Good luck.

So I've been running with the so called WiFried fix for a few days and as expected I still had disconnections, but as far as I can tell I only had one in 4 days and it was able to recover on its own.

Very well then, Wombat2K! Seems you've successfully implented 1 workaround at least. And I emphasize "workaround". But still...

The rest of your issues indeed seem RF noise related.

I suspect that considering the issue for me is mostly on recovering from sleep, it's possible the problem is due to the AP changing channels while the MBA was asleep.

Interesting observation. Can you second your suspicion with hard evidence your AP is dynamically switching channels with some hard evidence? Can't you lock your AP to 1 channel? Or, as was suggested here before, create different network name for both your 2.4 GHz and your 5 GHz network? Both seem interrelated.

Appears to be some confusion on your Mac as to which network to choose from. Which in turn may give us some clues here as to what is running amiss in some cases of Yosemite WiFi, the core business of this here thread.

I also noticed that the wifi setting seem to be shared between iOS and Mac OS X. For instance I noticed the MBA would connect to the 2.4Ghz band even though I had never set it explicitly.

That is even more fascinating. Could you steer clear of your MBA with iDevices for testing purposes for a while just to test if this switching to the unwanted 2.4 GHz band happens again?

A few pieces of the puzzle are starting to make some sense here, thank you! Seems we keep running in circles here around the RF implementation of Bonjour and Discoveryd. Thence BTW the partial success of shutting down AWLD0 and Airdrop.

One more question: (old suggestion again): do you still have an Internet connection if you switch your ipV.6 to link local only? I suspect not.

The reason I ask: while OSX has implemented ipV.6 as a vanguard system, not all ISPs can handle those ipV.6 addresses correctly even today.

The more to muddle our issue at hand...

I was unable to keep a constant wireless connection on my macbook pro. This just started a few days ago. It happened occasionally before I updated to Yosemite and then, after I upgraded to Yosemite, it happened all the time (every 20 or so seconds).

My fix (no issues for the last 20 minutes) was to update the firmware on my Airport Express; Open the Airport Utility > click on the Airport Express icon > click update.

Everything now seems to work well and it even seems faster.

Hope this helps someone.

Very well then, Wombat2K! Seems you've successfully implented 1 workaround at least. And I emphasize "workaround". But still...

The rest of your issues indeed seem RF noise related.

Yeah, it's definitely a workaround at best, but at least my MBA recovers as well as iOS devices do since 8.1, so at least my mac is now usable. I'm not sure how much RF interference is the issue, but certainly the signal strength seems to play a role, which is why I don't think anybody will be able to reproduce this issue at an Apple Store.

Interesting observation. Can you second your suspicion with hard evidence your AP is dynamically switching channels with some hard evidence? Can't you lock your AP to 1 channel? Or, as was suggested here before, create different network name for both your 2.4 GHz and your 5 GHz network? Both seem interrelated.

Appears to be some confusion on your Mac as to which network to choose from. Which in turn may give us some clues here as to what is running amiss in some cases of Yosemite WiFi, the core business of this here thread.

In my setup I use the 5 Ghz band with its own SSID. My main issue is that the 2.4 Ghz band is pretty unusable where I live, but the signal strength is higher than the 5 Ghz band, so I always need to make sure that it does not appear in my list of preferred wifi. Yet it always ends up re-appearing somehow and this seems to be triggered via iOS.

My fix (no issues for the last 20 minutes) was to update the firmware on my Airport Express; Open the Airport Utility > click on the Airport Express icon > click update.

Thanx, Mahk. This fix has been mentioned before, but confirming it works can't hurt in a monster thread like this.

At least you were not so impatient as to go out and buy yourself a new AXP before attempting what you did! Hope some more people read this.

My main issue is that the 2.4 Ghz band is pretty unusable where I live, but the signal strength is higher than the 5 Ghz band, so I always need to make sure that it does not appear in my list of preferred wifi. Yet it always ends up re-appearing somehow and this seems to be triggered via iOS.

Thence my suggestion to keep iOS devices out of range of your MBA: to see if the switching reoccurs, to ascertain iOS is doing the switching. Might be some Discoveryd component of Yosemite itself...

What about my ipV.6 question? Thanx!

Thank you for for your unselfish, sterling Christmas wi-fi bootcamp, Hexdiy!! I have nominated you for an award to people who I can't admit I am emailing on a subject i can't acknowledge exists - sigh - Apple anal secrecy

Have just checked for these files - only have discoveryd and ditto - helper and will now restart and look again as I experienced my first dropped wifi connection in days about 60 minutes ago.

I have been out of London for 10 days over Xmas - perhaps 1 (yes ONE) dropped wi-fi connection the whole time; 1st location, urban, numerous other wifi networks in view,  lots of different iOS and Android devices connected to same dual band router; 2nd location very rural, no other networks visible.  Auto connection on return to London, good connectivity but dropped earlier and would not reconnect to 5ghz channel - usual invalid password response crap.  1 iPhone and 1 iPad mini on each of the bandwidths.

Would be happy to share my wireless diagnostic reports with you if I knew how.  pauljohnson30@me.com.....

Have a great (post-Yosemite) 2015!!

Paul