Q: Mountain Lion no Wifi after wake from sleep

I am using a 2011 iMac, with the wireless turned off, I do not have transmit even installed and still every single time I open up my iMac from sleep mode the Ethernet is disconnected and will not reconnect.  It is very frustrating. 

Cabel, if you are still reading, will this be of use for you?

https://developer.apple.com/library/mac/#qa/qa2004/qa1340.html

It never fails for me now, if I forget to quit Transmit and close my MBP, when I open it again it's definitively getting frozen. I have been careful about quitting Transmit in the past week and I haven't had my MBP freeze, until last night, I forgot to quit it, and of course this morning I had a frozen Mac.

Thanks — not really relevant, but appreciated.

Our engineers have identified the exact cause of the problem, a particular Apple API call that's binding when the system tell us the IP address changes, and the call shouldn't be binding (obviously). We've added this to our Radar. I suspect quite a few applications, not just us, use this call.

My hopes of it being fixed in 10.8.1 are low since I've had no response to our bug yet, but I'm keeping on top of it!

That's really disappointing, I am going back to ForkLift then.

Thanks.

[ ... ] a particular Apple API call that's binding when the system tell us the IP address changes, and the call shouldn't be binding [ ... ]

So I'm assuming you're registering with SystemConfiguration for a callback in changes to network interfaces that match IPv4 / IPv6 -like strings (like: "State:/Network/Service/[^/]+/IPv4") ... but that should put the work on OS X to call *you* back with the updated / new keys, aside from the CFRunLoop to see if anything's changed.

I'm -really- curious what part of this is binding, based on what you're saying.

Also - if you are actively doing network traffic, do you guys currently make use of the kIOPMAssertionTypeNoIdleSleep notification listed above? Because I'd really hate for my machine to sleep during the middle of any activity. It's pretty trivial to implement - I even did it in python with ObjC / C wrappers: https://github.com/pudquick/pypmset/blob/master/pypmset.py

Would really love more details about what's "binding" here.

Here's what the engineers tell me, and you'll have to tell me what it means.

We're getting a system configuration callback that is telling us the IP address changed when the machine wakes from sleep. So when we get that, we stop our NSNetServiceBrowser instances. But when we go to start searching again (via searchForServicesOfType:inDomain:), that's when the whole system binds up. It doesn't in 10.7, it does in 10.8. Clearly even worst case scenario if that call is failing, the whole system shouldn't freeze up. Apple says that call should return immediately.

Hope this helps,

Cabel

I don't have Transmit installed and I close every application before I close the lid on my Macbook Pro.  When I reopen the lid after a deep sleep, I get the grey screen that the computer has crashed. 

This has happened consistently since I installed Mountain Lion.  I send the report to Apple every time.  Should I play with my wifi settings?  I have read on here that people think that is just a band-aid.  Do you think Apple will be releasing a fix for this?  Would they be able to do anything for me at the Genius Bar?  I can't give up half a day hanging at that kind of bar.

I suggest that if you find out what App is causing freezes in your system, send a complaint to Apple and request a refund, why in the world would we have to pay for an Application that causes a freeze and forces you to hard-reset your Mac?. Wether it's Apple's fault or the App's developers that's not for us to figure out and most definitively not for us to pay.

http://www.apple.com/support/mac/app-store/

Just wanted to add that like many others I do not have any of the software being discussed installed on my Mac, but still since upgrading to Mountain Lion everytime my Macs (iMac and MacBook Air) wake from sleep WiFi connection is lost. With exactly the same router, this never happened with Leopard, Snow Leopard or Lion! I really hope that 10.8.1 comes soon and that it addresses this issue. What amazes me though is how this WiFi issue got through Apple's testing.

I had the same problem.  Last night i fixed it with the Apple help.

There is problem in Keychain Access, which can be found in Applications/Utilities.

First you delete all your WiFi networks in network preferences and then delete all fields in Keychain Access that contain "Airport network password". 

That solved my WiFi problem.

Here is the link for detailed instructions:

http://support.apple.com/kb/HT4628

There choose :

Troubleshooting Wi-Fi issues in OS X Lion and Mac OS X v10.6

That should help.

Had high hopes for this, tried it twice but doesn't work for Mountain Lion for me, no change at all. Goes to sleep, no WiFi!

I spoke to Apple Care about the issue and they solved it for me. I had a WEP password on my wifi so I switched it to WPA2-PKS and I also switched the channel on my router from 6 which is the most interference prone to 9. Aparently, I don't know much about this, but it seems that these older WEP passwords cause problems with Mountain Lion

Have always used WPA, doesn't work for me with Mountain Lion.

I know little about router hardware and software. All I can add is maybe your channel is wrong as well? I tried everything listed in the forums and all didn't help untill I changed my router settings. It was really weird because one computer on mountain lion worked just fine.

I don't think it's too early to say, 10.8.1 has fixed it for me.

Spoke to soon, it's still there, 10.8.1 doesn't fix it, incredible!

Message was edited by: lwd