There is one question worth asking before touching the router: are other devices affected too?
If the phones, tablets, and other laptops all run fine while one device stutters, the router is almost certainly not the cause. Restarting the router, the first thing most people do, will change nothing.
The problem sits in one of three places: that device's settings, its hardware, or the way the router treats that device specifically.
First confirm it really is only one
This step sounds trivial but gets skipped, and skipping it means spending time down the wrong path.
Test with three different devices at the same time and place. Not "my phone was fine yesterday", but now, in the same room.
If it turns out every device slows at the same spot, this is not a device problem but coverage or capacity, covered separately in the guide to fixing slow Wi-Fi.
Identify the symptom first
Three different symptoms point to three different causes. Treating them as one sends the investigation in circles.
| Symptom | Where to look |
|---|---|
| Cannot connect at all | Stored network profile, password, MAC filtering |
| Connected but no internet | IP address, DNS, captive portal |
| Connected and working, but slow | Frequency band, drivers, power saving |
| Disconnects by itself | Roaming between access points, power saving, the adapter |
Forget the network, then reconnect
This is the correct first step for a single-device problem, and the one that works most often.
Devices store a profile for each network: password, encryption type, proxy settings, DNS servers. If one of those changes on the router while the old profile remains stored, the device keeps trying with information that no longer applies.
- Android: Settings → Wi-Fi → long-press the network name → Forget.
- iPhone: Settings → Wi-Fi → the information icon beside the network → Forget This Network.
- Windows: Settings → Network → Wi-Fi → Manage known networks → select the network → Forget.
- macOS: System Settings → Wi-Fi → Advanced → remove the network from the list.
Then reconnect by entering the password. If the problem is gone, you are done.
Check which band is in use
If the symptom is slowness, this is the next suspect.
Many routers broadcast 2.4 GHz and 5 GHz under one shared name. The device chooses for itself, and its choice is not always right. A laptop can cling to 2.4 GHz while sitting a metre from the router, because the 2.4 GHz signal looks "stronger" to it.
The 2.4 GHz band reaches further but is far slower and far busier, it shares space with microwaves, Bluetooth devices, and the neighbours' Wi-Fi.
A quick way to test. Temporarily give the two bands separate network names in the router settings, for example by adding a -5G suffix. Connect the problem device directly to the 5 GHz one. If the speed jumps, you have found the cause. Both bands are explained fully in the guide to the difference between 2.4 GHz and 5 GHz.
Drivers and system updates
On laptops specifically, the Wi-Fi adapter driver is a frequently overlooked cause. Windows sometimes installs a generic driver that works but is not optimal, particularly after a major update.
Get the driver from the laptop manufacturer's site, not from a third-party driver aggregator. Search by laptop model, not by adapter model.
If the problem appeared immediately after a system update, rolling the driver back to the previous version sometimes resolves it, on Windows via Device Manager → adapter → Properties → Driver → Roll Back Driver.
Adapter power saving
The operating system is entitled to switch off parts of the Wi-Fi adapter to save battery. The result: a connection that feels normal when plugged in but stutters on battery.
The characteristic symptom is a one- or two-second pause each time something starts loading after the device has been idle briefly.
On Windows, this setting lives in Device Manager → network adapters → Properties → Power Management. Untick the option allowing the computer to turn the device off to save power. There is also a separate setting in the power profile, under the wireless adapter category.
Randomised MAC addresses
Modern phones use a different MAC address for each network so that a user's movements cannot easily be tracked between locations. Good for privacy, but it causes problems on networks that identify devices by MAC address.
If an office, campus, or regular cafe network refuses your device while accepting others, try switching this off for that network only:
- iPhone: Settings → Wi-Fi → network information → turn off Private Wi-Fi Address.
- Android: Wi-Fi settings → network → Privacy → select Use device MAC.
Switch it off only for the problem network, not globally.
When the device connects but there is no internet
This is a class of problem in its own right. The Wi-Fi connection succeeds, but no traffic flows.
Check in order:
The IP address
If it begins with 169.254, the device received no address from the router. Forget the network and reconnect; if it recurs, check whether the router's DHCP addresses are exhausted.
DNS
If sites will not open but numeric IPs work, the problem is DNS. Set a public DNS temporarily to confirm, see the guide to public DNS.
Captive portal
On public networks, the login page sometimes does not appear on its own. Open a plain http address, not https, to prompt it. See the explanation of captive portals.
Proxy and VPN
Proxy settings left over from another network, or a VPN that failed to connect, stop traffic at the device itself.
When everything has been tried
Two last steps before concluding the hardware has failed:
Reset the network settings. Unlike a factory reset, this only clears network configuration, saved Wi-Fi networks, Bluetooth pairings, and mobile settings. Data and apps are untouched. On phones the option sits in the reset menu; on Windows, in Settings → Network → Network reset.
Test on another network. Take the device to a different Wi-Fi, or use tethering from another phone. If it misbehaves there too, the cause belongs to the device, the adapter may be failing, and a cheap USB adapter can serve as an adequate stopgap for a laptop.
If it works fine on another network, return to the router: there may be MAC filtering, a device limit, or a specific rule affecting only that device.
Frequently asked questions
Why is only my laptop slow when the phones are fine?
Most often because the laptop is on the 2.4 GHz band while the phones use 5 GHz, or because its Wi-Fi adapter driver has not been updated in a long time. Adapter power saving also frequently slows the connection when running on battery.
What does "forget network" do, and is it safe?
The device deletes the stored network profile, including the password and any settings attached to it. It is safe as long as you know the password to reconnect. It often resolves problems that appear after the router's settings change.
My device is connected but there is no internet. Why?
The Wi-Fi connection succeeded but the layer above it failed. Common causes: the IP address was not assigned correctly, DNS is not responding, or the device is still waiting for a captive portal login page that never appeared. Try opening a plain http address to prompt the portal.
Can a randomised MAC address cause problems?
Yes, on networks that restrict devices by MAC address or require registration. Modern phones use a random address per network for privacy. If an office or campus network refuses your device, switching this off for that network usually resolves it.
