WiFi is down on my Mac. What's the best way to fix lost WiFi connections on a Mac?

Mac WiFi not working? Are you having WiFi problems in Mac OS X Yosemite, Mac OS X El Capitan or macOS Sierra? Is your Mac not connecting to the internet? In this we list possible causes of a lost WiFi connection, and explain how to fix all your Mac's WiFi problems and get online.

This wireless networking feature will help you troubleshoot your Mac's OS X WiFi connection problems, and strengthen your WiFi connection should you be experiencing issues. If your Mac's WiFi is not working, these tips will help get it up and running again.

How to fix WiFi connection problems on Mac: Possible causes of a lost WiFi connection

Most of us take having an always-on wireless internet connection for granted: we're used to it just being there when we need it. Unless you're particularly unlucky and plagued by broadband problems, or live in a remote part of the country, fast access to the internet, allowing the streaming of audio and high-definition video, is the norm.

The problem with this is that things go wrong so infrequently that we're not used to having to fix them. When something does go awry with the WiFi connection on a Mac, it's tricky to know where to start.

How to fix WiFi connection problems on Mac

There are usually two possibilities; either there's a problem with your router or your broadband provider's network, or there's an issue with your own WiFi network. You can check the first by following your broadband provider's advice: check their website for instructions. If the problem is at the provider's end, there's not much you can do about it beyond complaining - although you should absolutely do that, in a polite but persistent way.

We're going to deal here with the part of the equation you can control: your local WiFi network, using a little-known tool tucked away in OS X called Wireless Diagnostics. This will help us to diagnose what exactly is wrong. We'll also discuss some practical tips for improving your Mac's WiFi signal, and generally improving the performance of your wireless network.

Read next: How to network Macs together and share files between Macs and PCs

How to fix WiFi connection problems on Mac: Wireless Diagnostics

In Mac OS X 10.8.4 Apple introduced a new tool called Wireless Diagnostics that can be used to help you get more from your wireless connection. It doesn't automatically change any settings, but can offer good advice on how to get the most from your Mac.

How to fix WiFi connection on Mac: Wireless Diagnostics

Here's how to use Wireless Diagnostics:

  1. Hold Option (Alt) and Click on the AirPort icon on the righthand side of the top menu bar. See above.
  2. Choose Open Wireless Diagnostics.
  3. Click Continue.

How to fix WiFi connection problems on Mac: Wireless Diagnostics

The first thing you'll notice is a dialog box explaining that as well as diagnosing problems with your WiFi network, Wireless Diagnostics can monitor your network for 'intermittent connectivity failures' and explaining that as well as placing a report on your Desktop, it will send the report to Apple, complete with some of your personal data. Clicking Continue at the bottom of the box gives your permission for that report and data to be sent to Apple. Ignore it for now.

How to fix WiFi connection problems on Mac: Wireless Diagnostics

Instead, if you're running Mac OS X Yosemite or later, go to the menu bar, click the Window menu and select Performance. Alternatively, press Cmd-5. In Mavericks and Mountain Lion, choose Utilities from the Window menu, then select the Performance tab (you might have to click Monitor Performance in the main dialog first).

Read next: How to use and control System Preferences on a Mac

How to fix WiFi connection problems on Mac: Monitor the graphs

How to fix WiFi connection problems on Mac: Monitor the graphs

In the window that opens when you click Performance, you'll see one or more graphs, depending on which version of OS X you're running. In Yosemite and later, there are three: one showing transmission rate, another displaying signal quality, and a third which shows signal and noise levels. Keep the window open for a few hours and monitor it.

The top graph displays the data rate in Mbps of your wireless network. The level of the graph will be dictated by your wireless router and other equipment you have connected to it. The important thing, in troubleshooting terms, is that the rate is reasonably consistent. The first indication of a problem with your network is sudden dips in the data rate, or a complete drop off.

The bottom graph, labelled Signal, displays both the signal strength and measured noise. Both are shown as dBM, or Decibel-milliwatts, a commonly used unit of the absolute power of radio signals. A reliable signal should have a signal strength of between somewhere between -60 and -10dBm and a noise level below -75dBm. The narrower the gap between the two lines on the graph, the more unreliable the signal is likely to be.

The middle graph, labelled Quality, displays the ratio of signal to noise over time. Ideally, it should be a straight-ish line with small spikes. If you notice frequent dips in the line, it's likely that something is interfering with your WiFi signal.

Read more: Mac OS X Yosemite WiFi problems | How to fix a broken internet connection

How to fix WiFi connection problems on Mac: Avoid interference

If you notice sudden increases in noise, the first thing to do is to try and identify when and why they occur. Does it happen, for example, when a wireless phone handset is in use, or when a microwave oven is switched on?

If you identify that a particular appliance is interfering with signals on your WiFi network, you have a couple of options. The simplest is to move the router away from the appliance that's causing the problem, if you can. Test several locations, varying the height of the router as well as its horizontal position. 

Here are some great tips for repositioning your WiFi router:

  • Move the router closer to the Mac. If you use primarily one device, such as a MacBook try moving your wireless router closer to the position of the MacBook.
  • Get the router up high. Avoid placing your Wi-Fi router at a height lower that furniture pieces, cabinets or other items.
  • Avoid other electrical devices. Other electrical devices, such as electric fans, motors, microwaves and wireless phones are all common causes of wireless interference. Try to position the router away from them, or move them away from the router.

If your wireless router has extendable antennae, then place one vertically, and one horizontally. This type of positioning will ensure that get the best reception for your wireless router. This is because the reception is maximised when both the device and antennea is along the same plane (so having one up and one horizontal boosts the chance of this).

You can get much better connection between your computer and a WiFi router by repositioning the router. 

How to fix WiFi connection problems on Mac: Use the 5GHz network

If that's not feasible, or doesn't help, and your router, Mac and iOS devices support 5GHz, you can force them to use the 5GHz network. 5GHz has a shorter range than 2.4GHz, but there's less interference because other domestic appliances don't use that frequency. You'll need to first separate the 2.4GHz and 5GHz networks on your router (check its manual to find out how to do it) and give them different names. If you have an AirPort Extreme or Time Capsule, the option is in the Wireless tab of AirPort Utility. Clive the Wireless Options button at the bottom of the window and click the box next to '5GHz network name.' Now give it a different name.

Once you've separated the 2.4GHz and 5GHz networks, you need to tell your Mac and iOS devices to join 5GHz in preference to 2.4GHz. In OS X, go to the Network Preferences pane in System Preferences, click on Wi-Fi, then the Advanced button, and drag the 5GHz network to the top of the list. On an iOS device, tap on Settings, then Wi-Fi. Tap on the 'i' next to the 2.4GHz network, and slide 'Auto-Join' to off.

You've now told your Mac and iOS devices to join the 5GHz network, leaving more room on the 2.4GHz frequency for those devices which need it.

How to fix WiFi connection problems on Mac: Install a WiFi extender

If you can't move your router, because of its fixed connection to your broadband or cable socket, consider buying a separate wireless access point (set it to Bridge mode if it has a built-in router), switching off the wireless access point on your router, and using Powerline adapters to connect the router and separate access point. That will give you more freedom in where to position the wireless base station on order to maximise its range and minimise noise.

You can place a second WiFi device closer to the router. Several WiFi extenders are available, or you can purchase an Apple base Station such as AirPort Express. This can be used to extend your wireless network.

Tip! Change the SSID (WiFi name) and password of the new device to the same as your current wireless router and modem. this will enable your Mac to pick whichever device is offering the better connection without you having to switch and enter a new password.

Read more: How to fix a frozen Mac | How to fix a Mac that won't shut down | How to fix a Mac that won't start up

How to fix WiFi connection problems on Mac: Solutions

How to fix WiFi connection problems on Mac: Update macOS or Mac OS X

Apple routinely issues software fixes and enhancements that can improve the performance of Mac OS X wireless connectivity. Click Apple > Software Update and make sure that you are running the latest version of AirPort software.

Read more: How to update Mac OS X or macOS

How to fix WiFi connection problems on Mac: Update macOS or Mac OS X

How to fix WiFi connection problems on Mac: Update router firmware

You should also check that your router is running the latest firmware. Updating your modem and router to the latest firmware depends on which router you are using.

Apple routers (such as AirPort Express, AirPort Extreme or Time Capsule) will check for updates periodically. When one is available, a budget will appear next to the AirPort Utility. Here is how to update the firmware on your Apple Base Station.

  1. Open AirPort Utility (Go > Utilities > AirPort Utility).
  2. Select the AirPort base station or Time Capsule.
  3. Click Update.

Most routers provided by an internet service provider, such as Virgin Media, BT Broadband or Sky, have a web-based interface that you access through Safari.

You should find the IP address (often on the back of the router or with some accompanying documentation), enter the digits (such as 192.168.0.1) into the Safari browser to access the web-based interface. Enter your admin name and password (again, these should be with the documentation). Here you may find an option to check for a firmware update, although we are finding more ISPs are updating modems to the latest version automatically.

How to fix WiFi connection problems on Mac: Restart all network devices

If you're having difficulty with your wireless network it's often a good idea to power down all your devices, including the WiFi router, your Mac and any other device connected to a WiFi network. Leave them off for a couple of minutes and then power them back up again.

The power cycle enables you the WiFi router to reconnect all the devices to the network, and it will free up any spare slots that are allocated to devices that are no longer connected (such as old laptops, laptops that were in your house temporarily or other local devices).

Which Apple WiFi router should you buy? AirPort models compared

How to fix WiFi connection problems on Mac: Require admin to turn WiFi Off

An option worth trying is to force Mac OS X to attempt to stay connected to the router. You can do this by insisting that Mac OS X asks you for your password to disconnect from a WiFi router. Here is how to perform this trick:

  1. Open System Preferences and click Network.
  2. Click on Advanced.
  3. Place a check in the box marked Turn Wi-Fi On or Off under Require Administrator Authorization To:
  4. Click OK.

How to fix WiFi connection problems on Mac: Channels

Finally, a word about channels. Routers do a good job of selecting channels automatically, based on what else is operating nearby. If, however, you open the Scan tool from the Windows menu in Wireless Diagnostics and notice that your router is operating on the same channel as another router nearby, you might want to consider changing it manually. Again, you'll need to consult your router's documentation to find out how.

Don't just move it to the next available channel, however. Channel frequencies overlap meaning that narrowband use five channels concurrently and wideband routers use seven. So, if you manually change channels, make sure you move at least five or seven channels away from the one your router is currently operating on.

As you make changes, keep monitoring the graphs in Wireless Diagnostics so you can see which ones make a significant difference to signal quality.

Extensive additional reporting by Lucy Hattersley

Further reading:

What is the point of Apple AirPort?

How to improve your WiFi signal

Which Apple WiFi router is best?

Best routers for Mac