Resolving Stubborn Wi-Fi Connection Problems in Mac OS X

Nov 30, 2012 - 49 Comments

A fair amount of Mac users have encountered long lasting Wi-Fi connection issues, whether it’s a dropping connection, a refusal to reconnect after waking from sleep, or any other number of oddities pertaining to wireless networking. Often these connection problems can be resolved with renewing a DHCP lease and changing the MTU size, but sometimes things are more stubborn and a wireless connection will continue to drop or throw unusual connection errors when waking from sleep. If you find yourself struggling with persistent wifi problems, try deleting all preference plist files associated with wireless settings in OS X:

Fixing Wi-Fi problems in Mac OS X

Fix Stubborn Wi-Fi Problems by Deleting Preference Files

Before beginning, be sure to have the wi-fi password of your primary network handy. You will need it to rejoin the network.

  • Pull down the Wi-Fi menu and turn Wi-FI OFF
  • Turn Wi-F off in OS X

  • From any Finder window, hit Command+Shift+G to bring up Go To Folder, and enter the following path:
  • /Library/Preferences/SystemConfiguration/
    Going to the Wi-Fi preferences folder

  • Locate the following files, copy them to the desktop for a backup, then delete them from the /SystemConfiguration/ folder:
  • com.apple.airport.preferences.plist
    com.apple.network.identification.plist
    NetworkInterfaces.plist
    preferences.plist

    Remove Wi-Fi preference files in Mac OS X to resolve connection problems

  • Empty the Trash and reboot the Mac
  • Turn Wi-Fi back ON from the Wi-Fi menu, join your preferred network as usual

This process forces OS X to create all new preference files for wireless networking, which can be an effective troubleshooting strategy if the wi-fi problems began after upgrading versions of Mac OS X and even installing incremental system updates.

The wi-fi connection should now work as expected unless there’s a deeper problem, whether it’s a compatibility issue with the router (often resolved by this DHCP and MTU fix), a problem the router itself, or something as simple as network interference (here’s how to check connection strength and interference issues), which can often be resolved by reconfiguring a routers physical arrangement or changing it’s broadcast channel.

Let us know if this worked for you, or if you have any other helpful wifi troubleshooting tips.

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Posted by: William Pearson in Mac OS X, Tips & Tricks, Troubleshooting

49 Comments

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  1. pm says:

    cool, ill try

  2. didi says:

    Creating a new network location in Network Preferences also worked for me

  3. Antonio says:

    If I do what you suggest, is it going to erase all my passwords for networks already saved in my MacBook Pro?
    Thank you,
    Antonio

    • martin says:

      Your passwords should be stored in keychain and should not be impacted by removing a preference file, but custom DNS and IP settings will be lost. I would write down your WiFi passwords somewhere beforehand though if there’s one you can’t remember.

      • Antonio says:

        Thank you, Martin. The problem is that many passwords are stored in the computer and there is no way to look for them. That makes the task of writing down beforehand quite difficult. I appreciate and I hope all of them are in the keychain.

      • roy says:

        Martin, That reminds me. I had an issue with my home wifi connection that was caused by duplicate keychains. I could connect to my network but overtime would get disconnected. I tried the preferences to no avail. The problem has not occurred since removing the duplicate wifi network system and login keychains.

  4. Hugh Briss says:

    The easiest thing to try first is to recycle the router (turn it off and back on). I had to do that every week or so on my old Netgear router, though my newer, top of the line, Netgear router doesn’t seem to require recycling.

  5. p2 says:

    Great—now what about a fix for the iPhone?!?!?!?!?

  6. trifero says:

    Nos ha jodío mayo con las flores…

  7. dave says:

    my imac does this while connected via ethernet….will it work for that as well?

  8. Brian says:

    I’m giving it a test drive over the next few days to see if it clears up a persistent bug I’ve had since installing M.L. where it would take two warm boots to load the wifi connection properly on a Airport Extreme as well as other routers that I access at different times in the course of my work.

    I’ll try to remember to report back with findings.

  9. Bill says:

    On my 2012 MacAir I seem to have cured my wifi connectivity problems by shutting off airport, opening key chain, under the Key Chain menu choose First Aid and run repair, and then turn airport back on. When I did this I noticed that errors were found in the key chain regarding my work network (a MS Exchange network).
    Four days in, no more slowness connecting, not connecting without reboot, or problems connecting upon wake from sleep.

  10. Peter says:

    It worked! Thank you so VERY much!

  11. Gary Mansell says:

    I have been suffering from WIFI re-connection problems when waking my MacBook Air running both Lion and Mountain Lion, but I have finally worked out what has been causing the problem.

    I suspect that many people who live in built up areas with many wireless networks around them may also be suffering from this too.

    The problem is 802.11d – when your WIFI wakes from sleep the first thing it does is to listen for a wireless network beacon signal to determine what country it is in and then it restricts it WIFI radio to _only_ listen on the frequencies for the country detected.

    Hence, if you have a neighbour with a wrongly configured country code then your machine will only listen on the frequencies for that country. I live in the UK and have a neighbour with a WIFI router wrongly configured for TW (Taiwan) – My Macbook then cannot see my Wireless N network as the channel is not one used in TW.

    I suggest checking the WIFI network country codes in your vicinity to see if you might be suffering from this using the WIFI Scanner built into Mountain Lion: http://osxdaily.com/2012/07/31/wi-fi-scanner-mac-os-x-mountain-lion/

    You can also check your syslog to see if it is configuring your WIFI radio for the wrong country:

    Nov 9 18:18:11 GarysMacBook kernel[0] : en0: 802.11d country code set to ‘TW’.
    Nov 9 18:18:11 GarysMacBook kernel[0] : en0: Supported channels 1 2 3 4 5 6 7 8 9 10 11 56 60 64 100 104 108 112 116 120 124 128 132 136 140 149 153 157 161 165

    My wireless N network is on Channel 48 and hence not seen – hence the failure to connect.

    The trouble is, I have put a letter out to all my neighbours explaining the problem and how they can fix it, but the WIFI router is still wrongly configured. I don’t know who owns the router as I have about 20 WIFI networks around me – about 10% of the time my WIFI still won’t connect to my WIFI network as it sees the TW WIFI Beacon before mine.

    I think that the 802.11d spec needs changing so that the country is not set on the first WIFI radio beacon detected as this can be wrongly configured. The strange thing is, I only see this behavour on my MacBook and not my iPhone 5 or my Windows laptop, so it must be possible to work around the spec.

    Maybe I can report my neighbour to OFCOM regulator in the UK, but I can’t see much hope in this.

    At least I know the problem, if I can’t fix it.

    I hope this helps some people as it was bugging the hell out of me.

    Gary

  12. biplav says:

    what to do to the files copied to desktop then?

    • Ignite Mindz says:

      If the method above worked, then you can just throw them in the trash. If it didn’t work you may want to delete the replacements that came up and put those files from the desktop back where they came from. I like to put a ~ in front of the file name instead of dragging it to the desktop. I’ve started doing this after I dragged somebody’s .plist to the desktop and totally lost it.

  13. herrhallen says:

    Be aware; if you use Rowmote. The app will not recognise you computer as is use to. You’ll have to name you computer again. In /system preferences/ network / share. Just name you computer as it use to be namned. Done and ready to go!

  14. Marcus says:

    I’v never experienced any WI-FI connection / dropping problems with Mountain Lion until I recently moved (2,000 miles) I’m using the same Modem & router but a slower internet connection ( 10Mbps down to 3Mbps) due to cost. Now I get dropped at least once a day. Would any of these suggestion from this article or the article from August 2 address my problem, or would it be a internet provider (Time Warner Cable) issue ?

  15. Indika says:

    Dont delete this file my laptop get worst then I put this file back problem gone
    com.apple.network.identification.plist

  16. Ben says:

    By any chances… is there any trick like this one working for bluetooth?

  17. akaii says:

    i do not have com.apple.network.identification.plist in my folder

  18. Brian says:

    So far so good. No Wifi problems to speak of over the past few days. MBP connects to Airport Extreme and other routers with no need to reboot.

  19. Aaron says:

    Any thoughts on percipient wi-fi connection problems on iPad? Second Generation? Sometimes even making a hot spot with my iPhone 4 doesn’t result in actual internet access on my iPad. Not the end of the world but frustrating.

  20. Jim says:

    This fix worked for me on our iMac, finally! I have tried each of the fixes that osxdaily has suggested and none have worked until this one.
    The WiFi connection would drop out after a certain period of not being used, then when we come back and try to reuse the iMac, after searching for WiFi signals it would latch onto an unlocked neighbors signal.

    Thanks so much for your help!
    Jim

  21. Nathaniel C. Gasque says:

    Thanks a million. Worked like a charm

  22. Greg says:

    I applied the solution and it seemed it worked for a while but the problem occurred again.

    I looked at the problem suggested by Gary that it has to do with the country code. I live now in Germany. I checked the setup of my Time Capsule and apparently the signal from there was with UK CC. I changed this setup to Germany and since then all goes smoothly.

    Actually I have an impression it goes faster!!! :)

    So check first the setup of your router.

    Cheers!

    Greg

  23. tassaque says:

    Worked for me after restart. thanks a lot.

  24. Anna says:

    Wow this worked! I’ve had this problem for so long tried everything and I ve been able to only work with Ethernet. Thank you thank you thank you for this post!!!!

  25. Norm says:

    I am not finding one of the plist files in my pref folder. I am using OS 10.9.1. and don’t see the com.apple.network.identification.plist. there is this one com.apple.network.eapolclient.configuration.plist
    Is it the same?

  26. GeoffM* says:

    I did all the things outlined at the start of this article and it made not an iota of difference. Then, on a whim, in preferences → network → advanced → I clicked ‘require password to change networks’. Magic! Back to the sparkling performance of yesteryear. I have been tearing out my (remaining) hair for weeks. Mac OSX v. 10.6.8. (It is still ok 24 hours later.)

  27. Jezza says:

    Thank you so much for this solution, which worked first time.

  28. Lori says:

    This fixed my problem. Thank you!

  29. neo246 says:

    Worked perfectly, Thank you

  30. johny why says:

    thanks! it worked!

  31. Kwong says:

    Thanks. worked first time.

  32. n3ll_s says:

    Thank you so much for this. I tried other fixes from other sites (such as deleting the airport entries in the keychain) but wasn’t successful. This made problem go away.

  33. JuL says:

    I tried almost everything and at the end the easiest solution fixed my issue with the bad wifi connection. Just turn Bluetooth off!! It seems that Mavericks has trouble when both services are turned on. I hope that Apple is working on an update. I need my bluetooth working because of my wireless mouse.

  34. Sheena Phillips says:

    deleting the plist files as described worked perfectly for me – thank you so much

  35. rams says:

    Thank you Thank you Thank you!
    I was ready to fly-kick this iMac into tomorrow.

  36. J says:

    Really works.. Thanks!

  37. Lillian says:

    AMAZING fix! My computer was working perfectly in the U.S.. but after moving overseas, it just stopped. I’ve never had problems before and figured it must be the wifi where I am, but no one else had the problems I did.. Thank you genius solution poster!!

  38. Daniel says:

    Guys, you made my day! I was getting so frustrated and after a few days i have been able to fix it thanks to your advice.

    Cheers!

  39. Harry says:

    Thanks this is the only thing that works. This problem is a real nuisance and “pain in the neck” problem but thanks to this solution it now works. It seems to erase it’s memory of the settings that are causing the problem and now my late 2013 iMac connects with my wiFi every time……thanks a million…..it is much appreciated

  40. Maddy says:

    Amazing!!! Worked first try and I am not “tech savvy” so to speak. Thanks

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