1. Create a new folder on your Desktop called ‘wifi prefs backup’ or something obvious
2. Turn off Wi-Fi from the menu item in the upper right corner of OS X
3. Go to the Finder (the smiley face icon in the Dock), and hit Command+Shift+G to bring up the Go To Folder command, choose the following path exactly:
4. /Library/Preferences/SystemConfiguration/
5. com.apple.airport.preferences.plist, com.apple.network.identification.plist, NetworkInterfaces.plist, preferences.plist
6. Move all of these files into the folder you created in step 1 on the desktop (you can also delete them if you’re confident and have made a backup)
7. Reboot the Mac
8. Turn on Wi-Fi from the wireless network menu again in the upper right corner of OS X
9. IF YOUR WI-FI WORKS NOW, GREAT, BUT FOR MOST USERS, YOU’RE NOT QUITE FINISHED YET! NOW YOU NEED TO CREATE A NEW CUSTOM NETWORK LOCATION.
10. UIT ANY OPEN APPS THAT ARE USING WI-FI OR NETWORKING (CHROME, SAFARI, MAIL, ETC)
11. Go to the Apple menu and select “System Preferences”
12. Choose the “Network”
13. Click the “Location” menu and select “Edit Locations”, hen click the [+] plus button to create a new location, “Fixing My WiFi” and click “Done” to add it"
14. Next to “Network Name” , join the wi-fi network and authenticate with the router password as usual
15. Next, select the “Advanced” button in the lower corner of Network preferences, then go to the “TCP/ IP” tab, choose “Renew DHCP Lease”
16. Next go to the “DNS” tab, and on the left side “DNS Servers” list, click the [+] plus button, to add a new DNS server* – I use 8.8.8.8 and 8.8.4.4 for Google DNS but you can choose whatever you want
17. Next, choose the “Hardware” tab, then next to ‘Configure’ choose “Manually”, Change “MTU” to “Custom” and set the MTU number to 1453, then click on “OK”
18. Finally, choose the “Apply” button to set your network changes
