Though Apple has largely resolved the wi-fi issues that persisted in some Macs with prior OS X releases, some users with OS X El Capitan may encounter wireless networking issues after updating to the latest OS X release. Typically the wi-fi problems are in the form of dropping connections or strangely slow speeds, and the good news is they’re usually an easy fix.
For most Mac users who are experiencing issues with wi-fi connections in OS X El Capitan, simply ditching old preference files, followed by creating a new network location with custom DNS settings and an MTU change is enough to resolve whatever wi-fi problems they may have had. This is a multi-step process but not particularly difficult.
You’re going to be deleting a few system level preference files and creating a new network location. Before getting started, you should start and complete a backup of the Mac with Time Machine. Don’t skip backups.
/Library/Preferences/SystemConfiguration/
com.apple.airport.preferences.plist com.apple.network.identification.plistcom.apple.wifi.message-tracer.plistNetworkInterfaces.plistpreferences.plist
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.
* If you’re not sure what DNS to use, you can find the fastest DNS servers for your situation with a benchmarking utility. Typically the fastest servers are Google DNS and OpenDNS, but results may vary per region.
Now wireless connectivity should be working flawlessly in OS X, and back at full speed. Try things out by navigating around the web, doing a speed test, and just using the internet as usual.
The solution outlined above almost always works to resolve wireless networking issues in OS X, particularly if they occur after updating to a new version of system software or a point release.
If you’re still having trouble with wi-fi in OS X 10.11 or later, try the following:
Have you had wi-fi issues or speed problems with OS X El Capitan? Did this work to resolve them for you? Let us know in the comments, or if you had another solution, let us know that too!