Welcome to our Mac Wi-Fi troubleshooting guide, which offers fixes for situations where Wi-Fi isn’t working, your Mac refuses to connect to the internet, you MacBook won’t connect to WiFi but other devices will, or your wireless signal strength is poor.
Most of us take an always-on wireless internet connection for granted: we’re used to it 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.
When things go wrong with your Wi-Fi or your broadband connection it’s not just your email you’ll be missing, but also your social networking life and your evening’s Netflix viewing. Equally, if your Mac has a slow internet connection you can find yourself tearing out your hair.
There are three main reasons why Wi-Fi stops working: there’s a problem with your router, your broadband provider’s network is down, or there’s an issue with your own Wi-Fi network. Less commonly, there may be an issue with the macOS software you’re running. We cover all these scenarios in this article.
We address problems with a weak Wi-Fi signal in a separate article here: How to improve your Wi-Fi signal.
Check Apple’s software
In the past when Mac users have updated their computers to a new version of macOS they have sometimes encountered Wi-Fi problems. This was a big issue with the original version of El Capitan: following the update, many users found their Macs could no longer connect to their wireless network.
Apple issued an update to the software, but this wasn’t an easy fix for MacBook Air owners who could only connect to the web via Wi-Fi. When we had this problem we had to update our Mac to the new version of macOS while sharing the connection from our mobile phone.
You may well have to do the same if it’s a software update you need, in which case do be careful about going over your data allowance!
You may also experience problems with WiFi if you are running a beta version of MacOS. We had a lot of trouble with WiFi dropping when we were running the High Sierra beta, in fact the issues have only recently been resolved by the 10.13.2 update.
Find out if there are issues with the latest version of macOS here.
Check Apple’s Wi-Fi recommendations
When your Mac attempts to connect to a Wi-Fi network, macOS checks for issues. If any are detected, you’ll see recommendations in the Wi-Fi status menu, which you can access by clicking on the Wi-Fi logo at the top right of your screen.
Check with your broadband provider
If the problem is at the provider’s end, there’s not much you can do about it beyond complaining – and you should absolutely do that.
Even if the network isn’t down, it might still be the provider’s problem (or BT’s problem). For example, sometimes the cabling to the house can be at fault; if your web connection often cuts out during bad weather it may be because water is getting into the cables.
Reboot your router
To establish whether the problem lies with your router, you should turn it off and on again. To powercycle your router you need to disconnect it from power for about 30 seconds, then plug it in and turn it back on.
Reboot your Mac
As with the router, it’s also a good idea to turn your Mac off and on again.
If there’s still an issue after you’ve rebooted, try turning the Wi-Fi off and then waiting a few seconds before turning it back on again to force it to scan for available networks again.
To turn Wi-Fi off and on again click on the Wi-Fi logo in the menu at the top right of your Mac and select Turn Wi-Fi Off.
Try disconnecting Bluetooth. This is a fix that has worked for some people. Click the Bluetooth icon at the top right (the runic B next to the Wi-Fi icon) and select Turn Bluetooth Off.
Forget the network
You may find that forcing your device to forget the network can help. Turn off Airport, go to System Preferences > Network, then select Wi-Fi in the list on the left and then click Advanced. Select the network you wish to forget, press the (-) and agree to Remove.
Once you’ve done this your Mac and other devices using your iCloud Keychain will not join that network.
Now try connecting to the network again, adding the password when requested.
Keep your router cool
If things still don’t work, check your router isn’t overheating. Don’t cover it up or hide it away where there isn’t adequate ventilation, because if it gets too hot it won’t work as well.
Check your router’s location
Another thing to check is your router’s location. You will get a better signal if it’s not on or near any large metal surfaces – so don’t sit it on a filing cabinet, for example, and don’t put it right next to a radiator.
Move your laptop closer to your router and see if you get a signal from there. If it turns out the signal is fine when you’re right next to the router, it’s likely that something in your house or office is causing interference. We have advice about where to locate your router in our article about improving Wi-Fi range.
Find out if something is blocking the signal
There are lots of reasons why the signal strength can be weaker in certain locations and not others. For example, thick walls in old houses can make getting a signal in one corner of the house impossible.
If there is a lot of metal in the building that can also cause issues with your Wi-Fi, so it might be worth checking what materials were used in the construction of your property.
You can use an app called NetSpot (£7.99) to create a map of the Wi-Fi signal in your building. Move your Mac around and chart the signal strength in various locations to get an idea of where the signal is stronger and where’s it’s weak.
If you have identified the problem as being an issue with the signal strength in certain parts of your building we recommend getting a Wi-Fi extender like one of these Powerline adaptors.
When you set up the Wi-Fi extender make sure you change the SSID (Wi-Fi name) and password of the new device so it’s the same as your current wireless router and modem, to enable your Mac to pick whichever device is offering the better connection without you having to switch and enter a new password.
Alternatively the problem may be other electrical devices, such as fans, motors, microwaves and wireless phones. Does your Wi-Fi drop at the same time as you use the microwave? Because they’re both using radio waves you can get interference when you turn your microwave on.
Try to position your router far away from these devices.
Use Apple’s Wireless Diagnostics
You can also get an idea of whether other devices are causing your signal to drop by using macOS’s built-in Wireless Diagnostics utility.
To generate a graph like the one shown above, follow these steps:
- Open Wireless Diagnostics. Either search for it using Spotlight (Cmd + spacebar), or hold Option/Alt and click on the Wi-Fi icon at the top right of the screen, then select Open Wireless Diagnostics.
- Before you click Continue to run a report, go to the menu and click on Window > Performance (or hit Alt + Cmd + 5)
This will generate three graphs that will tell you about the transmission rate, signal quality, and signal and noise levels. If you monitor this for a few hours you may be able to identify whether there is a problem.
The top graph displays the data rate of your wireless network in Mbps. The level of the graph will be dictated by your router and other equipment you have connected to it. The important thing, in troubleshooting terms, is that the rate is reasonably consistent. If you are seeing dips in the data rate, or a complete drop-off, it indicates that there is a problem.
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 Wi-Fi signal.
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 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.
If you notice sudden increases in noise, try to identify when and why they occur. Does it happen, for example, when a wireless phone handset is in use, or when a microwave is switched on? If you identify that a particular appliance is interfering with the signal, move the router away from the appliance that’s causing the problem.
You could also try varying the height of the router as well as its horizontal position to see if that has any effect on the reception when the interfering gadget is in use.
Check the competition
Your Wi-Fi connection may also be suffering because of other networks nearby, sharing the radio waves with you – particularly if you’re in a built-up area.
To find out what other traffic is in your area your could try the WiFi Explorer app(£19.99).
WiFi Explorer will help you see what other networks are in your area. It provides a lot more information than you normally see in the list of available networks on your Mac, which you see if you click on the Wi-Fi logo in the menu bar.
Choose a unique network name
Now you have seen these different Wi-Fi networks, make sure you configure your Wi-Fi network with a unique name so that it doesn’t conflict with the names of other nearby networks.
Change your Wi-Fi channel
You could go some way to counter competition from other Wi-Fi networks by changing the channel you’re on. There are 13 channels, and of them all but 1, 6 and 11 overlap. You’d be wise to pick a channel as far away from your neighbours’ if possible.
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.
The steps you need to follow to change the channel on your router will depend on your router software. To access your router software you need to know the IP address of your router. Most routers have an IP address of http://192.168.0.1 or http://192.168.1.1, although BT routers are usually http://192.168.1.254.
Open your web browser and type the IP address into the address bar and press enter. This will bring up your router software. Look for the channel information and log into your router to change it.
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.
Alternately you could configure your Wi-Fi network channel to Automatic so that it selects the best channel to use.
Use the 5GHz band
Those channels mentioned above relate to the 2.4GHz band. Another way to improve your Wi-Fi signal could be to switch to the 5GHz band. The 5GHz band offers more bandwidth than the 2.4GHz band and is less susceptible to interference because other domestic appliances don’t use that frequency.
In the UK there are some legal restrictions placed on this band regulated by Ofcom, and for this reason switching to 5GHz in the UK won’t necessarily fix your problem in the same way as it might in the US. But it’s still worth a try.
To use the 5GHz band on your dual-band router you’ll need to first separate the 2.4GHz and 5GHz networks on your router (check its manual to find out how) and give them different names. If you’ve got an AirPort Extreme or Time Capsule, the option is in the Wireless tab of AirPort Utility.
Click 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 macOS, go to the Network 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. There’s more information about how to do this in our guide to improving Wi-Fi signal here.
Check your security settings
One piece of advice is not to hide your network – it might sound like this makes things more secure, but it doesn’t actually protect it and can cause reliability issues.
Instead, if you want your network to be secure, use WPA2 Personal security.
Run Apple Diagnostics
If you still haven’t solved your Wi-Fi worries you could use Apple Diagnostics to check for Wi-Fi or network issues.
To do so follow these steps:
- Disconnect all external devices (except the keyboard and screen).
- Shut down the Mac, then turn it on while pressing and holding D.
- When you see the screen asking you to choose your language do so, then watch as the progress bar indicates that your Mac is being assessed. This takes 2-3 minutes.
- If problems are identified, Apple Diagnostics will suggest solutions.
Reset your SMC, PRAM or NVRAM
Reset the PRAM and the SMC (System Management Controller) is worth a try. This process is covered here: How to reset your Mac’s NVRAM, PRAM, and SMC.
Change the DNS setting for your network
Changing your DNS settings is also recommended, but like resetting SMC, PRAM and NVRAM it’s not for beginners.
You need to start by deleting your Wi-Fi preference files, but we advise you to back them up first!
- Find the Wi-Fi preferences by opening the Finder and choosing Go > Go To Folder and typing: /Library/Preferences/SystemConfiguration/
- In this window locate the following files and drag them to clearly labelled backup folder on your Desktop:
- Reboot the Mac.
- Turn on Wi-Fi and see if it works.
- If Wi-Fi doesn’t work you need to create a new Wi-Fi network location, adding custom MTU and DNS details.
- Before you do this, quit any apps that might be using Wi-Fi or the network.
- Go to System Preferences > Network and choose Wi-Fi. Click on the menu beside Location and choose Edit Locations, click the + to create a new location and name it something memorable. Click Done.
- Join the Wi-Fi network, using your usual router password.
- Click on Advanced and under the TCP/IP tab choose Renew DHCP Lease. Go to the DNS tab and add 126.96.36.199 and 188.8.131.52 to the DNS Servers list. (Those are the Google DNS, which are generally the fastest options, but you can add something else if you prefer.)
- Choose Hardware and Configure Manually.
- Change MTU to Custom and set it to 1453, click OK and Apply.