Resolving Stubborn Wi-Fi Connection Problems in Mac OS X
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:
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
- From any Finder window, hit Command+Shift+G to bring up Go To Folder, and enter the following path:
- Locate the following files, copy them to the desktop for a backup, then delete them from the /SystemConfiguration/ folder:
- Empty the Trash and reboot the Mac
- Turn Wi-Fi back ON from the Wi-Fi menu, join your preferred network as usual
/Library/Preferences/SystemConfiguration/
com.apple.airport.preferences.plist
com.apple.network.identification.plist
NetworkInterfaces.plist
preferences.plist
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.
cool, ill try
Creating a new network location in Network Preferences also worked for me
Me too, that is basically what is described in this article but less extreme.
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
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.
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.
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.
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.
Great—now what about a fix for the iPhone?!?!?!?!?
Nos ha jodÃo mayo con las flores…
my imac does this while connected via ethernet….will it work for that as well?
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.
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.
It worked! Thank you so VERY much!
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
what to do to the files copied to desktop then?
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!
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 ?
Dont delete this file my laptop get worst then I put this file back problem gone
com.apple.network.identification.plist
By any chances… is there any trick like this one working for bluetooth?
i do not have com.apple.network.identification.plist in my folder
Me too =(((
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.
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.
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
Thanks a million. Worked like a charm
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