Mac WiFi Keeps Disconnecting After Sleep: 8 Fixes

If your Mac WiFi keeps disconnecting, usually after the lid has been closed or the machine has been asleep, you are not alone. It tends to show up after a macOS update, and the cause is often a setting or a stale network preference, not faulty hardware. Work through these fixes in order. Each one is quick to try and the early ones solve most cases.

1. Rule out the router first

Check whether your other devices stay connected. If your phone drops off too, restart the router. If only the Mac has the problem, carry on. It also helps to test on another network, such as a phone hotspot. If the Mac behaves there, the problem is between the Mac and your router.

2. Turn WiFi off and on, then restart

Click the WiFi icon in the menu bar, switch it off, wait ten seconds and switch it back on. If it still drops, restart the Mac. You can also do the toggle in Terminal:

networksetup -setairportpower en0 off
networksetup -setairportpower en0 on

On some Macs the WiFi interface is not en0. Run networksetup -listallhardwareports and look for the Wi-Fi entry to get the right device name.

3. Install pending macOS updates

Open System Settings, go to General, then Software Update. WiFi bugs introduced by a release are usually fixed in a point update, so make sure you are on the latest version for your Mac.

4. Forget the network and rejoin

Open System Settings, then Wi-Fi, find your network under Known Networks and choose Forget This Network. Rejoin and enter the password again. This clears a corrupted saved profile, which is a common cause of drops after sleep.

5. Change the Private Wi-Fi Address setting

Recent macOS versions use a private (rotating) MAC address on each network. Some routers handle this badly and disconnect the device. Open System Settings, then Wi-Fi, click Details next to your network and set Private Wi-Fi address to Fixed or Off. Reconnect and see if the drops stop.

6. Check power settings

• Open System Settings, then Battery, and turn off Low Power Mode to test, because it can reduce network activity while the Mac sleeps.
• Under Battery, then Options, look at Wake for network access. If you rely on the Mac staying reachable while asleep, set it to Always, or at least while on power adapter.

7. Change DNS and flush the cache

Sometimes WiFi stays connected but pages stop loading, which feels like a disconnect. Open Wi-Fi, then Details, then DNS, and add a public resolver such as 1.1.1.1 or 8.8.8.8. Then flush the cache:

sudo dscacheutil -flushcache
sudo killall -HUP mDNSResponder

8. Reset the network preferences

If nothing has worked, remove the saved network configuration so macOS rebuilds it. Make a Time Machine backup or copy the files somewhere safe first. Then quit all apps, open Finder, press Shift-Command-G and go to /Library/Preferences/SystemConfiguration/. Move these files to the Desktop:

• com.apple.airport.preferences.plist
• NetworkInterfaces.plist
• preferences.plist

Restart the Mac. It creates fresh copies, and you will need to rejoin your WiFi networks and re-enter any custom network settings, such as a static IP.

Dig deeper with Wireless Diagnostics

Hold the Option key and click the WiFi icon to see the channel, signal strength (RSSI) and noise. From the same menu you can open Wireless Diagnostics, which records the connection and can show what happens at the moment of a drop. In Terminal, sudo wdutil info prints the same details. A strong signal with a high noise reading, or a weak signal from a far-away router, points to an environment problem, not a Mac fault.

If drops continue on every network you try, and only on this Mac, run Apple Diagnostics or book a Genius Bar check, because it could be the hardware. Most of the time, though, forgetting the network, fixing the private address setting or resetting the preference files is enough.