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


This is solution 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 by holding the Command button while you click on the file names.
    1. 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

  7. Remove those matching files by placeing them into the Trash without emptying.
  8. 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”
  9. When the Mac has booted back up as usual, go back to the Wi-Fi menu and choose “Turn Wi-Fi On” and select the SAD6-Wireless network.
  10. Pull down the  Apple menu and choose “System Preferences”, then select “Network”
  11. Choose Wi-Fi from the left list in the Network panel and then click the Advanced button.
  12. Now select the “Hardware” tab and set the ‘Configure’ option to “Manually”, then adjust the “MTU” option to “Custom”
  13. Enter the number “1453” and hit OK.
  14. You are done.  I hope that your WiFi experience is better.