Wi-Fi Slow Only on Your Mac: Renewing the Lease and More

3 Sep 2026

Chen every other phone, tablet and computer connects normally but one Mac feels painfully slow, it is tempting to blame the router or internet provider.

However, when the problem affects only one Mac, the cause is more likely to be local to that device. The Mac may have retained an outdated network address, joined the wrong access point, selected a congested Wi-Fi band, inherited faulty DNS settings or allowed an application to consume the connection in the background.

The solution is to confirm that the wider network is healthy, then work through the Mac’s network settings from the least disruptive fix to the most advanced.

First, Confirm the Problem Is Limited to the Mac

Test another device on the same Wi-Fi network and in the same location.

Compare:

Website loading
Video streaming
File downloads
Video calls
Speed-test results
Access to local servers or printers

Make sure the devices are connected to the same network. Many routers broadcast separate guest, 2.4GHz, 5GHz or 6GHz networks, and different devices may be using different access points.

If every device is slow, the problem is probably with the router, broadband connection or wider network.

If only the Mac is affected, continue with the checks below.

Restart Wi-Fi Before Changing Anything

Open Control Centre or the Wi-Fi menu and turn Wi-Fi off.

Wait approximately ten seconds, then turn it back on and reconnect.

You can also restart the Mac:

Apple menu > Restart

A restart reloads the wireless services, clears temporary network processes and closes applications that may be interfering with the connection.

If the speed returns only temporarily, the restart has not fixed the underlying cause, but it confirms the problem may involve a process or network configuration on the Mac.

Check the Mac’s Signal Strength

Wi-Fi performance can vary considerably across a room, even when the connection indicator appears normal.

Move the Mac closer to the router or wireless access point and test again.

Poor signal may be caused by:

Thick walls
Metal furniture
Filing cabinets
Large monitors
The Mac being beneath a desk
Electrical equipment
Neighbouring wireless networks
Distance from the access point

If the Mac becomes fast when moved closer, the issue is coverage or interference rather than a damaged internet connection.

Make Sure the Mac Joined the Correct Network

Open:

System Settings > Wi-Fi

Confirm that the Mac is connected to the intended network.

Watch for:

A guest network
A mobile hotspot
An older router
A weak wireless extender
A similarly named neighbouring network
A corporate network with restricted access

The Mac may automatically join a remembered network even when a better one is available.

Disconnect from the unwanted network and select the correct one manually.

Renew the DHCP Lease

A DHCP lease gives the Mac its local IP address and other network information.

The router normally renews this information automatically, but the Mac may occasionally retain an expired, conflicting or unsuitable address. Renewing the lease asks the network for fresh connection details.

Apple includes a Renew DHCP Lease control in the Mac’s TCP/IP network settings.

To renew it:

Open System Settings.
Select Network.
Choose Wi-Fi.
Select Details beside the connected network.
Open TCP/IP.
Select Renew DHCP Lease.
Confirm the action if prompted.

The connection may disconnect briefly before returning.

Test the speed again.

What Renewing the Lease Can Fix

Renewing the DHCP lease may help when the Mac has:

An IP-address conflict
An expired network lease
Incorrect router information
Problems accessing local devices
Internet access that works intermittently
A connection that became unreliable after changing networks
Slow performance after the router was restarted or replaced

It does not normally fix weak signal, broadband congestion or a failing router.

If there is no improvement, continue troubleshooting.

Check the Mac’s IP Address

In the same TCP/IP settings, examine the Mac’s IPv4 address.

A normal private network address often begins with:

192.168

10.

172.16 to 172.31

An address beginning with:

169.254

usually means the Mac could not obtain a proper address from the router.

Renew the lease and restart the router where appropriate.

On a business network, do not restart network equipment without approval. The DHCP server may be managed centrally.

Forget and Rejoin the Wi-Fi Network

The Mac stores the network’s password and configuration. That saved record can become outdated after router, security or password changes.

Apple’s current Mac instructions allow a known network to be removed from the Advanced Wi-Fi settings and joined again as a fresh connection. Forgetting it may also remove the network from other devices using the same iCloud Keychain, so consider that before proceeding.

Before forgetting the network, make sure you know its password.

Then:

Open System Settings.
Select Wi-Fi.
Scroll down and select Advanced.
Find the affected network.
Select the More Options button beside it.
Choose Remove From List.
Confirm Forget.
Reconnect and enter the password.

Test the connection again.

Check Which Wi-Fi Band the Mac Is Using

Modern routers may offer:

2.4GHz
5GHz
6GHz

2.4GHz

Offers longer range but is often slower and more congested.

5GHz

Usually faster at shorter to medium distances and less affected by common 2.4GHz interference.

6GHz

Can provide excellent performance on compatible Macs and routers but has shorter range and weaker wall penetration.

If the router uses separate network names, connect the Mac to the faster band and test.

If it uses one combined name, the router automatically decides which band the Mac uses. Moving closer to the access point or restarting Wi-Fi may encourage a better connection.

Compare Wi-Fi with Ethernet

Connect the Mac to the router using Ethernet where possible.

You may need a USB-C or Thunderbolt Ethernet adapter.

If Ethernet is fast but Wi-Fi remains slow, the broadband connection is probably healthy. Focus on:

Signal strength
Interference
Wi-Fi settings
The router’s wireless configuration
The Mac’s wireless hardware

If Ethernet is also slow, investigate software, DNS, VPNs, security tools or the internet connection itself.

Disconnect USB Hubs and External Drives

USB 3 devices and poorly shielded cables can interfere with wireless signals, especially in the 2.4GHz band.

Temporarily disconnect:

USB-C docks
External SSDs
Hard drives
Hubs
Display adapters
Capture devices
Card readers

Test Wi-Fi with only the charger connected.

If performance improves, reconnect devices individually until the slowdown returns.

Possible fixes include:

Replacing the cable
Moving the device away from the Mac
Connecting it to another port
Using a better dock
Switching the Mac to 5GHz or 6GHz Wi-Fi

Check for Downloads and Cloud Synchronisation

A Mac may feel as though Wi-Fi is slow when one application is consuming most of the available bandwidth.

Check for:

iCloud Drive uploads
iCloud Photos synchronisation
OneDrive
Dropbox
Google Drive
Time Machine network backups
macOS updates
App Store downloads
Game downloads
Large email attachments
Video uploads

Open Activity Monitor and select the Network tab.

Sort by:

Sent Bytes
Received Bytes
Sent Packets
Received Packets

Look for applications transferring unusually large amounts of data.

Pause non-essential transfers and retest the connection.

Check VPN and Security Software

VPN clients route network traffic through another server and can significantly reduce performance.

Disconnect the VPN temporarily and test again.

Also review:

Web-filtering software
Antivirus network inspection
Corporate security agents
Parental controls
Proxy applications
Privacy tools
Network-monitoring utilities

Apple’s troubleshooting guidance notes that VPN and other third-party security software can affect network connectivity.

Do not remove business security software without permission. Instead, report the test result to the organisation’s IT provider.

Check Proxy Settings

An incorrectly configured proxy can make websites slow or prevent them from loading.

Open:

System Settings > Network > Wi-Fi > Details > Proxies

For a normal home connection, proxy options are usually disabled unless a specific application or network requires them.

Do not remove settings on a managed business Mac without checking with the administrator.

If an unfamiliar proxy is enabled and the Mac is personally owned, investigate which application or profile added it.

Try a Different DNS Service

DNS translates website names into network addresses.

When DNS is slow or unreliable, websites may appear to pause before loading even though the actual connection speed is healthy.

Open:

System Settings > Network > Wi-Fi > Details > DNS

Make a note of the existing entries before changing them.

Common public DNS options include:

1.1.1.1

1.0.0.1

or:

8.8.8.8

8.8.4.4

Add the preferred DNS servers, apply the change and test several websites.

Apple provides a DNS section within the Mac’s network details for entering DNS servers and search domains.

On a business network, use the DNS servers supplied by the organisation. Public DNS can interfere with internal systems, filtering and domain services.

Test Whether DNS Is Actually the Problem

Try opening a known website normally.

Then test a direct IP connection using Terminal:

ping -c 4 1.1.1.1

Next test a domain name:

ping -c 4 apple.com

If the IP address responds quickly but the domain name is delayed or fails, DNS may be involved.

Ping is only one diagnostic signal. Some networks and servers restrict it, so a failed response does not automatically prove the internet is down.

Flush the DNS Cache Carefully

macOS normally manages its DNS cache automatically.

A restart is the safest way to clear temporary DNS state.

Terminal commands for manually flushing DNS vary across macOS versions and are often repeated online without context. Avoid using commands written for old releases unless the exact macOS version and command have been verified.

Changing DNS servers, restarting the Mac and renewing the DHCP lease are safer first steps.

Run Wireless Diagnostics

macOS includes Wireless Diagnostics for analysing Wi-Fi and internet connection problems.

To open it:

Quit unnecessary applications.
Connect to the affected Wi-Fi network.
Hold the Option key.
Select the Wi-Fi icon in the menu bar or Control Centre.
Choose Open Wireless Diagnostics.
Follow the instructions.

Apple states that Wireless Diagnostics analyses the connection and provides detected issues and possible solutions without changing the Mac’s network settings. It also creates a diagnostic archive that can be supplied to an administrator or support provider.

Pay attention to warnings about:

Signal quality
Congestion
Conflicting networks
Router configuration
Connection drops

Use the Wi-Fi Details from the Option Menu

Hold Option and select the Wi-Fi icon.

Depending on the macOS version, you may see technical details such as:

Channel
Band
Signal strength
Noise
Transmit rate
Security type
Access-point identifier

A poor signal-to-noise relationship can explain why one Mac is slow even though another device appears acceptable.

The numbers are most useful when comparing:

Different rooms
Different access points
Before and after disconnecting a dock
2.4GHz versus 5GHz
The affected Mac versus another Mac

Check for Private Wi-Fi Address Problems

macOS can use a private Wi-Fi address to reduce tracking between networks.

This is normally beneficial, but some older, restricted or access-controlled networks expect the Mac to use a registered hardware address.

Open the affected network’s details and review Private Wi-Fi address.

Temporarily changing this setting may help only when:

The network uses MAC-address registration
The router reserves an address for the Mac
Access is tied to a specific hardware address
The network administrator has advised it

Apple includes Private Wi-Fi Address controls in the network’s Wi-Fi settings.

Do not disable privacy features routinely to troubleshoot ordinary slowness.

Check iCloud Private Relay

iCloud Private Relay can affect how Safari and some unencrypted traffic reach websites.

Temporarily disable it for a controlled comparison only if:

Safari is slow but other applications are not
Particular websites behave differently
The network blocks or limits Private Relay
The issue follows the Apple Account rather than the Wi-Fi connection

Do not assume Private Relay is the cause of general Wi-Fi slowness.

If all applications are slow, investigate the wider network path first.

Test Another Browser

Open the same website in Safari and another browser.

If one browser is slow while the other is normal, the problem may involve:

Extensions
Cached website data
Browser profiles
Content blockers
Proxy extensions
Privacy tools
A damaged browser installation

Disable extensions temporarily and restart the browser.

Do not reset all network settings because one browser extension is misbehaving.

Check Browser Extensions

Extensions can inspect or redirect traffic.

Temporarily disable extensions related to:

VPNs
Advertising
Shopping
Password management
Privacy
Security scanning
Download management
AI assistants

Reopen the browser and test again.

Remove extensions you do not recognise or no longer use.

Check the Date and Time

Incorrect date and time settings can disrupt secure website connections and authentication.

Open:

System Settings > General > Date & Time

Enable automatic date and time where appropriate.

This is unlikely to reduce raw Wi-Fi speed, but it can make websites and online services appear unreliable or slow.

Install macOS Updates

Open:

System Settings > General > Software Update

Install supported updates after backing up important data.

Updates may correct:

Wi-Fi compatibility
Roaming behaviour
Security problems
Sleep-related network faults
Driver issues

Apple recommends updating macOS when a Mac can connect to another network, because updates may contain relevant fixes.

Also update router and dock firmware where available.

Test After Waking From Sleep

Some Macs become slow only after waking.

Try this sequence:

Restart the Mac.
Test Wi-Fi immediately.
Put the Mac to sleep.
Wake it.
Test again.

If the slowdown appears only after sleep:

Renew the DHCP lease
Toggle Wi-Fi
Disconnect the dock
Update macOS
Forget and rejoin the network
Review VPN and security software
Check whether another access point was selected after wake

This pattern can help distinguish a persistent configuration problem from a sleep-and-wake issue.

Review Network Locations

macOS supports network locations, which allow different groups of settings for home, office or another environment.

A location containing old DNS, proxy or network-service settings may affect only the Mac.

Apple notes that network locations are useful when the same network service requires different settings in different places.

Check:

System Settings > Network

Open the network actions menu and review the active location where available.

Create a clean test location rather than deleting a working business configuration.

Test in Safe Mode

Safe Mode limits some third-party startup software and performs basic checks.

If Wi-Fi is normal in Safe Mode, the slowdown may be caused by:

A login item
A VPN
Security software
A network extension
Cloud-sync software
Background utilities

Restart normally after testing.

Do not leave the Mac in Safe Mode as a permanent solution.

Test with a New User Account

Create a temporary account from:

System Settings > Users & Groups

If the connection is normal in the new account, investigate the original user’s:

Login items
Browser extensions
Proxy settings
VPN configuration
Cloud applications
User-specific software

If every account is slow, the problem is more likely to be system-wide, hardware-related or connected to the network.

Check the Router’s Device List

Open the router or wireless-controller dashboard where authorised.

Check whether the Mac:

Has a valid IP address
Connected to the expected access point
Uses 2.4GHz instead of 5GHz
Has a low link rate
Is subject to parental controls
Has bandwidth limits
Is assigned to a guest or restricted policy
Appears more than once with different private addresses

On a managed business network, provide the Mac’s name, Wi-Fi address and the time of the slowdown to the network administrator.

Avoid Randomly Deleting Network Configuration Files

Older Mac troubleshooting guides often recommend deleting files from:

/Library/Preferences/SystemConfiguration

This can remove network interfaces, VPN settings and other important configuration.

It may also be inappropriate for current macOS releases or managed devices.

Use supported controls such as:

Renew DHCP Lease
Forget This Network
Network locations
Wi-Fi settings
Wireless Diagnostics

before manually changing system files.

When the Wi-Fi Hardware May Be Faulty

Consider a hardware problem when:

Every Wi-Fi network is slow
Bluetooth is also unreliable
The Mac has extremely short wireless range
Wi-Fi disappears completely
Performance remains poor in Safe Mode
The fault began after impact or liquid exposure
Another Mac performs normally in exactly the same location
Ethernet works properly
Apple Diagnostics reports a wireless fault

Apple Diagnostics can test certain internal components, including wireless hardware. On current macOS versions, the available diagnostic options vary by Mac and system version.

A Sensible Troubleshooting Order

When Wi-Fi is slow only on one Mac, follow this sequence:

Confirm that other devices are fast on the same network.
Turn Wi-Fi off and back on.
Restart the Mac.
Check the signal and move closer to the router.
Confirm the correct network and access point.
Renew the DHCP lease.
Forget and rejoin the network.
Disconnect docks, hubs and external drives.
Pause cloud sync and large downloads.
Disconnect VPN and test approved security tools.
Check proxy and DNS settings.
Run Wireless Diagnostics.
Update macOS, the router and connected docks.
Test after sleep, in Safe Mode and in another user account.
Check router policies and access-point information.
Run Apple Diagnostics if every wireless network remains slow.

The most useful clue is whether the problem follows the Mac across different Wi-Fi networks.

Need Help with Slow Wi-Fi on Your Mac?

Slow Wi-Fi on one Mac can be caused by an expired network lease, DNS delays, interference, cloud synchronisation, VPN software or failing wireless hardware. Changing router settings randomly can disrupt other users without fixing the affected device.

Hamilton Group can analyse the Mac’s wireless connection, review DHCP and DNS settings, identify interference and determine whether the fault is caused by macOS, the network or the hardware.

Call 0330 043 0069 or visit hgmssp.com to speak with one of our IT experts.