Perhaps one of the more ubiquitous problems that OS X users encounter is a periodic inability to maintain a steady Wi-Fi connection. While for many people Wi-Fi is relatively stable, for others there may be times (sometimes quite frequent), where the connection will drop, give an error, and otherwise refuse to join. There are many reasons why Wi-Fi connections may do this, including everything from electromagnetic interference to faulty configurations, so troubleshooting it may be daunting. However, if you find yourself running into this issue regularly, then there are a few quick fixes that should get you up and running again.

Reset Equipment

Naturally the first approach is to turn off your Wi-Fi router, and also turn off your Mac’s Wi-Fi radio. Then turn these back on after a few seconds. More often than not, these quick resets will reload your network configuration in a way that will work properly.

Use custom DNS servers

While not specifically a Wi-Fi problem, if you are unable to load sites or are getting “Server not found” errors, then you can try using custom DNS servers other than those provided by your ISP (and subsequently by your router). To do this, go to the Network system preferences, select your connection, and then click the Advanced button. In the panel that drops down, select the DNS tab, and then click the plus button under DNS Servers to add new servers. In here, add the following two server IP addresses (these are Google’s public DNS servers):

8.8.8.8
8.8.4.4

Configure IPv6 to Link-local only

Most TCP connections online still use IPv4, so you can try limiting the newer IPv6 connections to the broadcast domain of your local network by setting it to Link Local only. To do this, in the same network configuration panel, go to the TCP/IP tab, and then choose Link Local Only from the Configure IPv6 menu. When done, click Apply and see if this helps your network stability.

Create a new network location

OS X supports network locations, which are separate configurations for your various networking ports, that allow you to quickly switch between a work networking environment, to a home one, to one at a public location. This is particularly useful if you have a static IP address at one location but have a dynamic one at another location. Since OS X will create new configurations for each location, you can use this to in essence start fresh and hopefully bypass any configuration errors causing your connection problem:

1. Go to the Network system preferences.
2. Choose Edit Locations from the Locations menu.
3. Click the plus sign to add a new location.
4. Close the location panel, configure your Wi-Fi port according to your needs, and click Apply.

Delete your entire network configuration

Sometimes the easiest approach is to bypass OS X’s interfaces for managing system configurations, and go right to the configuration files themselves. In this case, the network configuration files in OS X are located in the following directory:

Library > Preferences > SystemConfiguration

In this folder, remove all files that reference either entworking, wifi, or airport in their names, and remove them. These include the following, along with a folder called CaptiveNetworkSupport:

com.apple.airport.preferences.plist
com.apple.captive.probe.plist
com.apple.network.eapolclient.configuration.plist
com.apple.wifi.message-tracer.plist
NetworkInterfaces.plist
preferences.plist

A final approach to this issue is to simply remove all contents of the SystemConfiguration folder, which is a more crude approach, but will require the system to recreate it and all its contents from scratch. Keep in mind that doing this may require you to set up your computer networking name, and other similar details again, but these might be trivial options that aren’t needed for the most part.