After upgrading OS X from Lion to Mountain Lion on my Macbook Pro, I started having serious wifi problems. At first, I would loose my wifi connection once a day, and I could recover it only with a reboot. After trying many different solutions I found in blogs and forums about how to fix wifi problems under Lion and Mountain Lion, my wifi connection simply got worse. For the past few days, I could only connect to the internet using an Ethernet cable.

Here is the list of things I tried:

  • Recreating the network interfaces
  • Removing/adding my wifi network from the list of preferred networks
  • Deleting my wifi network password from my keychain
  • Resetting the SMC
  • Resetting the PRAM
  • Deleting the “/System/Library/SystemConfiguration” folder and the cache folder (I don’t remember exactly, but I think it was “/System/Library/Caches”)
  • Removing IO80211Family.kext and installing IO80211Family.kext from Snow Leopard (in /System/Library/Extensions)
  • Reinstalling Mountain Lion’s IO80211Family.kext file (what I beieve are the wifi drivers)
  • Restarting the network interface and renewing the DHCP lease many times
  • Trying different MTU values (1280, 1300, 1453)

None of all that helped. Although some of these solutions have helped other users. So I decided to call Apple Support line. I am still entitiled to complimentary support because I bought Mountain Lion less than 90 days ago. The tech guy was very nice with me and took time to go through a whole procedure to try to fix the problem. Most of the things I had already tried though. In the end, my wifi interface was still not working properly. I told him that I had done a clean install of Mountain Lion, but that I hadn’t tried the wifi connection before reimporting my settings with the Migration Assistant. He told me I should try that because during the tests he asked me to boot using the Recovery partition and to start browsing for help in Safari from there. This was working, so he suspected one of the settings or applications I imported is causing the problem. He mentionend software like Parallels Desktop could in theory interfer with the network interface. So he suggested I do another clean install and check the wifi connection, import my account settings and recheck my wifi connection, import my application and recheck my network settings, etc. in order to pinpoint where the problem is coming from.

I thought doing all those tests would take quite a bit of time, so I decided to uninstall Parallels 7 completely and see if that helped. It did not. Then I thought about Hands Off! which is also tighly connected with the network interface. So I unsinstalled Hands Off! completely (including my rules and settings). After rebooting, My wifi network interface was finally working. I still have to wait a few days though to make sure it will keep working properly, but for now it is working properly even after waking my Macbook Pro (Late 2011) from sleep.

I then decided to reinstall Parallels Desktop 7 and Hands Off! (2.0.4) and everything is still working fine for now. It seems to have been Hands Off! causing the trouble, but I uninstalled it just after uninstalling Parallels Desktop 7, so I cannot rule out Parallels 7 entirely.

UPDATE: It’s been three days now that I fixed this issue and my wifi connection is running fine since then. 🙂

One thought on “[Solved] Wifi connection problems after upgrading to Mountain Lion

  1. My Macbook Pro a 2011 has had WiFi connection issues after my Mac comes out of sleep. The WiFi can take a while to establish a connection to my home network. I have also tried many of the things you tried. It is strange that I only have one connection saved and why it should take almost a minute to reconnect is very unusual. But then again after owning several Mac’s I have certainly had WiFi issues in the past. I am not sure if some of these issues are with how Apple addresses certain security settings or if its router firmware and hardware that is just not compatible. I suspect from what I have read from Wireless network people is that Apple tests only with Apple routers and that Apple typically does not totally follow standards for all Routers and more important a lot of router makers don’t concern themselves with some of those compatibility issues with Apple products. In my opinion though I find WiFi very inconsistant as a whole in compatibility. Especially with added features, security settings and other settings that can affect a device that may or may not support that setting or function. What’s funny is that I have had several PC’s accessing the same router and never have a single problem. All this tells me is that router makers worry more about Windows compatibility then they do other devices.

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