Fix Wi-Fi Problems in macOS Sierra

Sep 22, 2016 - 52 Comments

Fix Wi-Fi Problems in MacOS Sierra

Some Mac users are reporting wi-fi difficulties after updating to macOS Sierra 10.12. The most common wireless networking problems seem to be either randomly dropping wi-fi connections after updating to macOS Sierra, or an unusually slow or delayed wi-fi experience after updating a Mac to Sierra 10.12.

We’ll walk through some some-tested troubleshooting steps to resolve wireless networking troubles with a Mac running macOS Sierra.

What we’re going to cover here involves a longstanding approach to resolve most common wi-fi issues with Mac OS, composing primarily of removing existing wi-fi settings and then recreating a new network profile with some custom settings. These steps should resolve the most typical manifestations of wi-fi networking problems seen with macOS Sierra, which are the following:

  • The Mac disconnects from wi-fi when wakes from sleep
  • macOS Sierra drops wi-fi connections or disconnects from wireless at random
  • Wi-Fi connections are unusually slow or have a higher ping than usual after updating to macOS Sierra

The approach may fix other networking related issues as well, but those are the primary wifi problems aimed to be addressed by this walkthrough. We’ll also cover some additional generic wi-fi troubleshooting tips that may be helpful if the primary two approaches do not resolve the difficulty.

It is recommended to backup your Mac before beginning any of this process. Time Machine makes it easy, but you can use whatever backup method you’d like.

1: Remove Existing Wi-Fi Preferences in macOS Sierra

This is going to involve removing some system configuration files, therefore you should backup your Mac first, just in case. Do not remove any other system configuration files.

  1. Quit any active applications that are using wi-fi or the internet (Safari, Chrome, etc)
  2. Turn OFF wi-fi by selecting the wi-fi menu bar item and choosing “Turn Wi-Fi Off”
  3. Open Finder in macOS and pull down the “Go” menu and choose “Go To Folder” (or hit Command+Shift+G to get there quickly)
  4. Enter the following path exactly into “Go to folder” window and choose “Go”
  5. /Library/Preferences/SystemConfiguration/

  6. Locate and select the following files in the SystemConfiguration folder
  7. com.apple.airport.preferences.plist
    com.apple.network.eapolclient.configuration.plist
    com.apple.wifi.message-tracer.plist
    NetworkInterfaces.plist
    preferences.plist

    fix macOS sierra wifi problems by trashing wireless preferences

  8. Remove those matching files, you can either place them into a folder on the desktop as a rudimentary backup, place them into the Trash without emptying, or actually delete them
  9. After those matching wi-fi configuration files are out of the SystemConfiguration folder, reboot the Mac by going to the  Apple menu and choosing “Restart”
  10. When the Mac has booted back up as usual, go back to the Wi-Fi menu and choose “Turn Wi-Fi On” and join your typical wireless network

When the Mac boots back up and wi-fi is enabled again, for many users their wireless internet connection will immediately work again as expected. If that’s the case, be satisfied with the relatively easy troubleshooting process and you don’t need to proceed any further.

It’s often a good idea to reboot the wi-fi router the Mac is connecting to as well, which can resolve some simpler wi-fi router issues that sometimes pop up with certain router brands and Macs. This is easiest in a home environment where you can just unplug the router, let it sit for a minute or so, then plug it back in again. Obviously for a work or school computing environment that may not be possible though.

Is your wi-fi working? Great, then you don’t need to do anything else. But what if your wi-fi is still dropping, still slow, still losing a wi-fi connection randomly when waking from sleep or for no apparent reason? Read on for more troubleshooting tips.

2: Set a New Network Location with Custom MTU and DNS

Assuming you’ve already removed the wi-fi preference files in the first major troubleshooting section above and wi-fi is still problematic with mac OS Sierra, you can proceed

  1. Pull down the  Apple menu and choose “System Preferences”, then select “Network”
  2. Choose Wi-Fi from the left list in the Network panel
  3. Pull down the “Location” menu and select “Edit Locations”
  4. edit locations

  5. Click on the [+] plus button to create a new network location with an obvious name like “Custom WiFi Fix”
  6. make new network location

  7. Use the Network Name dropdown menu and select the wi-fi network you want to connect to
  8. Now choose the “Advanced” button in the corner of the Network panel
  9. Go to the “TCP/ IP” tab and choose “Renew DHCP Lease”
  10. renew dhcp

  11. Now go the “DNS” tab, and under the “DNS Servers” list section click on the [+] plus button, adding each IP onto it’s own entry: 8.8.8.8 and 8.8.4.4 – these are Google Public DNS servers that are free to use by anyone but you can pick different custom DNS if you’d prefer
  12. set custom DNS

  13. Now select the “Hardware” tab and set the ‘Configure’ option to “Manually”, then adjust the “MTU” option to “Custom” and number to “1453”
  14. custom MTU setting

  15. Now click on “OK” and then click on “Apply” to set the network changes

Exit out of System Preferences and open an app that uses the internet like Safari, your wi-fi should work great now.

This troubleshooting method of specifying DNS (and, importantly, using known to be working DNS) with a lower custom MTU setting of 1453 is time tested and has routinely worked for resolving some of the most stubborn wi-fi networking problems in macOS Sierra and going further back to many prior Mac OS X releases too, each of which is often accompanied by some limited examples of wireless networking difficulties.

3: Still Having Wi-Fi Trouble? Here Are More Troubleshooting Tips

If you’re still having trouble with wi-fi in macOS Sierra 10.12 or newer, you can try the following additional troubleshooting steps:

  • Are you certain you are on the macOS Sierra final public release? The first GM seed was different from the final version (build 16A323), but you can download macOS Sierra again from the Mac App Store if need be and update to the final version
  • Reboot the Mac into Safe Mode by rebooting and holding down the SHIFT key, when booted into safe mode, reboot again as usual – this is a process which dumps caches and can fix some finicky basic trouble
  • Reset SMC on the Mac – requires a reboot and power cable
  • Reset PRAM / NVRAM on the Mac – requires a reboot
  • Power cycle the wi-fi router (disconnect it from power for 30 seconds or more, then turn it back on)
  • Update the Wi-Fi router firmware if any update is available
  • Avoid 5 GHz G and B networks if possible, aim to join a 2.4 GHz network N if one is available for faster speeds
  • Temporarily disconnect Bluetooth and see if wi-fi works while Bluetooth is disconnected
  • If all else fails, consider downgrading macOS Sierra back to El Capitan using Time Machine
  • Still having wi-fi difficulties? Consider visiting an Apple Store or contacting official Apple Support

Have you experienced any wi-fi issues with MacOS Sierra? Does wi-fi drop or appear slower than usual for you after updating to macOS Sierra? Did the troubleshooting steps above fix the problem you experienced? Let us know your experience in the comments below.

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Posted by: Paul Horowitz in Mac OS X, Tips & Tricks, Troubleshooting

52 Comments

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  1. CLK says:

    Are these beta testers? I went to the App Store and look for the upgrade and it doesn’t show availability for me to update.

    • MarcDeveloper says:

      Hi CLK,

      No it’s final release for all. To update search Sierra in the AppStore and download it. When finish download it start upate process. (downolad has +/- 5Gb)

  2. CLK says:

    Oh never mind, I found it. They have changed the layout in the App Store.

  3. Adam says:

    This article helped me getting the wifi back. Thank you!

  4. Victor says:

    Do I recall correctly that there were similar problems for some users when upgrading from Yosemite to El Capitan? If so, why cannot Apple ensure that such problems are fully resolved before unfortunate users have to sort these problems out for themselves. Of course there are always going to be some bugs when upgrading, but this one seems like it should and could have been predicted before releasing this update. Or are we all becoming unpaid Beta testers? I won’t be upgrading from El Capitan for at least three months, and Apple certainly won’t compensate me for any upgrade impacts on my business.

  5. LR says:

    Really helpful! I have not upgraded, but am going to try these fixes for El Cap – THANK YOU!

  6. Tom says:

    For some reason, I do not have this folder

    /Library/Preferences/SystemConfiguration

    Any reason why?

    Thanks

  7. Gurudatta says:

    This is long pending issue in Apple. When ever they release any new OS, They have the same issue I think they don’t know how to fix this .

    Regards
    Gurudatta N.R

  8. Neil Fiertel says:

    Your approach to many problems seems as if it is retrograde and derivative of how one had to problem solve in 1994.. How about letting apple know of the problems so they can solve it..or God forbid wrot My a script that solves the problem..your long tiresome processes are not doing is any favours..

  9. Adam says:

    Turns out the problem persists after booting up the computer again. Any ideas to solve it so that there is no need to delete the .plists each bootup?

  10. vdiv says:

    Love the shooting in the dark, everything with the kitchen sink, hail-marry approaches to problems like this. Wasn’t the main reason to use a Mac that it just worked?

  11. Dick Schiltz says:

    STEP 1 is clear with instructions but substep 6:
    Remove those matching files, you can either place them into a folder on the desktop as a rudimentary backup, place them into the Trash without emptying, or actually delete them

    cannot be done because of the ‘move to trash’ error 43!! Further, there is no ‘remove or delete’ location in the software and the keyboard ‘delete’ key doesn’t either.

    So what’s my next step to REMOVE or DELETE those 6 items listed?

    • faber says:

      I don’t have that problem but here is what I did: copied the files, then deleted them from the folder.

      So I would drag and drop the files, that’s how you move files on the Mac. You can send them to the Trash if you want, I copied mine to the desktop then deleted the ones in the folder.

    • CPG says:

      FWIW, Cmd+Opt+Delete has been OS X shortcut to delete immediately (bypassing Trash). I Haven’t upgraded to macOS yet but I hope that still works.

  12. Barry Sullivan says:

    I am having wifi issues and found this page. When I go to the system configuration folder all I see is bundles no plist files at all. I tried holding down the Option key to go to library and also the Go to Folder way.I have 3 Macs and no plist files on any of them. I have been setup as an admin. Did macOS Sierra change any of that.

  13. Dan Uff says:

    How about doing something like this for the iPad Pro? I have been loosing my Wifi ever since going to iOS 10.

  14. Barry Sullivan says:

    About my issue. I called Apple and they say those files are hidden in macOS Sierra. The Apple advisor and I made changes in System Preferences to see if the wifi will not fail during sleep mode.

  15. Julian Duncan says:

    Will I need to do this with the new Safari 10.00 as Im still running on OS X Yosemite

  16. Bob Wheaton says:

    I was having intermittent problems with wifi on my MBP in El Cap. Finally fixed it by simply turning off bluetooth. Tried a bunch of other stuff to fix but this is what did it for me. Rock solid again!

  17. Nathan k says:

    This wifi issue also effects internet sharing. Sierra randomly stops broadcasting. There is no fix as it is a bug in sierra.

    I can confirm this because I’ve tried to fix this up to erasing the hard drive and doing a fresh install of sierra working from scratch and the bug comes back.

    • Andrew says:

      Sierra is heavily dependent on iCloud and is constantly phoning home and doing things online. I have a low quality internet connection (small town America, no infrastructure) and Sierra is always having problems, iCloud errors, different error messages, etc. Unfortunately it’s not just wi-fi, if the network itself is slow or unstable then Sierra has a real problem behaving. Some people may perceive that as wi-fi problems but for me it’s just Sierra itself uses the internet too often for Photos, iCloud, Files, Documents, Storage, Siri, Spotlight, all these things that would be nice to turn off to preserve what little bandwidth we have.

  18. Zachary Horner says:

    Thanks a bunch! Super helpful and fixed the problem.

  19. Kimppikoo says:

    Same problem here. After upgrading to Sierra, WiFi speed dropped to 50-60 Mbps from 280-300 Mbps. Bluetooth off, and the speed was back! *SIGH*

  20. Paul Raff says:

    CAN’T BELIEVE IT – WIFI DROPPED WHILE I WAS TYPING THE FACT THAT I FOLLOWED ALL THE STEPS TWICE AND IT STILL DROPS OFF!!! I can’t turn off bluetooth because I’m running an iMac so keyboard and mouse with not work. Apple this is basic crap!!!!!!

  21. Fabio says:

    Hi, regarding the wifi issue (my imac mid2011 won’t reconnect after sleep): if I delete those files I lose all networks and stored passwords?

  22. Paul Werner says:

    First off, THANK YOU for the great article. This really worked for me, as I have been having wifi problems since El Capitain. The first “fix” did not work, and waking up from sleep presented the same searching and ultimately turning wifi on and off to get it to connect. HOWEVER, for me, the second “fix” of setting a new network location and manually entering customer MTU and alternate DNS settings really did the job! Now it is like it is supposed to be. Again, thanks for the very comprehensive article.

  23. cam says:

    Thank you… Method 1 worked perfectly for me.

  24. Ed says:

    Unfortunately, none of the methods worked for me. Ever since the upgrade to macOS Sierra I’ve had WiFi issues. As soon as my iMac locks when the screensaver starts, after I unlock, the only way I can get WiFi to work again is to turn it off and on again.

  25. Emm says:

    Awesome! Thanks a lot, first step was enough for me. My problem was an infinite loop of a temporary “Authenticating..” status then just dropping connection.

  26. Briolet says:

    Thanks, this solved my problem.
    For me it was worse. During updating to Sierra, the update failed en forced me into continually rebooting my MacBook pro (13 inch medio 2010). I had to reinstall El Capitan from my Time Machine backup.

    In that backup I had no wifi. The mac failed to show any wifi station. When doing a network test, the wifi stations were in the log, meaning the antenna is working and getting signal.

    Than I tried a clean install of Sierra. That also failed, hanging up my mac twice. It was still hanging in the installation procedure after 12 hours.

    Than restoring El Capitan for the second time. Stil no Wifi, but now I got it working with above procedure. The only difference was that the ‘Preference” folder was locked for me. I had to change the rights of ‘everyone’ from “no access” to “read only”.

    No Sierra for me for a long time. It looks it is screwing up things on some hardware.

  27. Chris L says:

    Resetting my wifi settings worked! Thank you!

  28. timur says:

    It helps, thank you

  29. Paul says:

    Thanks! Between this and the photo analysis, I was a bit frustrated after Sierra install. Hopefully a little smoother now.

  30. Ben says:

    When I upgraded to MacOs Sierra my iMac wasn’t automatically connecting to my home wifi network.

    If you forget you home network and use the Assist Me… option in the Network System Preferences. Then, run through the tutorial. These steps worked for my older iMac (late 2011 model).

    1. System Preferences
    2. Forget/Delete home network
    3. System Preferences – Assist Me…
    4. Run through tutorial, don’t forget to Apply after you are done.

    You will be prompted to Save Configuration.

    Hope this helps!

  31. Kyle says:

    After upgrading to Sierra my iMac would no longer reconnect to my WiFi network when waking from sleep.

    The only fix that had any consistent effect was disabling “Wake for network access” under the “Energy Saver” settings in System Preferences.

    Now the iMac reconnects to the WiFi every time.

    I hope this helps someone!

  32. thegamer304 says:

    I really hope this works… I was disappointed when Siri didn’t work

  33. Anthony says:

    You’ve gotta be kidding – after all these various updates we STILL have wi-fi issues? I have been suffering with these problems and have spend many hours trying to resolve them overtime an update occurs. Wish Steve Jobs were still around – these problems would never have surfaced.

  34. Farhana Zaman says:

    Thanks. I used the first method and it’s working nicely.

  35. Derrick Bell says:

    Performed the upgrade yesterday from El capitan. ReceivING a “no hardware installed” prompt for my WiFi adapter. This is a ’12 aluminum macpro. Reset SMC and NVRAM already with no luck. Any suggestions?

  36. David says:

    Thank you! This helped with my extremely slow ping time, everything else seems to be working.. THANK YOU!

  37. Evie says:

    Thank you so much, removing the configurations (your first recommendation) worked! :-)

  38. Christophe says:

    Thank you. One remark:

    “Avoid 5 GHz G and B networks if possible, aim to join a 2.4 GHz network N if one is available for faster speeds”

    For me far better wifi on 5ghz though !!

  39. Cmgisc says:

    One note- 2.4GHz, while technically capable of greater ranges in theory, is almost always more congested. Additionally, 2.4 is limited to 20MHz, whereas 5ghz supports 20/40 on n and 20/40/80 (and soon 160Mhz) channel bonds on wireless Ac.

  40. Dony says:

    I already tried this with El Capitan and it didn’t work. Very frustrating.

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