After installing a macOS update, you might notice that your mac wifi slow after update. Pages take forever to load. Video calls freeze constantly. Downloads that used to finish in seconds now drag on for minutes. This is a known issue. macOS updates can change network settings, enable new features like AWDL or Private Relay, or reset certain preferences that affect Wi‑Fi performance. Consequently, your once‑fast connection becomes sluggish.
Several factors contribute to this post‑update slowdown. DNS cache corruption is a common culprit. AWDL interference from AirDrop scanning can become more aggressive. Bluetooth and Wi‑Fi may start interfering on the 2.4 GHz band. New security features like content filters might throttle traffic. Additionally, your router may have compatibility issues with the updated Wi‑Fi drivers.
If your mac keeps disconnecting from wifi, see our pillar post. This guide, however, focuses specifically on when your connection remains stable but painfully slow after an update. For baseline speed measurement, check out our Mac Wi‑Fi signal strength guide (cluster post #1).
Quick Tests Before You Start
Before diving into deep fixes, run these quick tests. They will help narrow down the problem.
Test 1: Check another device. Use your phone or another laptop on the same network. If those devices also have slow Wi‑Fi, the issue is your router or internet service, not your Mac.
Test 2: Try a different network. Take your Mac to a coffee shop or friend’s house. If speed returns to normal, your home router settings need adjustment.
Test 3: Perform a full power cycle. Restart both your Mac and your router. This simple step often clears post‑update temporary glitches.
Test 4: Open Activity Monitor. Go to Activity Monitor > Network tab. Look for any process using high bandwidth. Software update leftovers sometimes continue downloading in the background.
If the problem is isolated to your Mac and started immediately after the update, proceed with the fixes below.
Fix 1: Reset Network Configuration Files (Post‑Update Cleanup)
macOS updates occasionally corrupt network configuration files. Resetting them forces your Mac to recreate fresh settings. This often restores lost speed.
Steps:
- Quit System Settings.
- Open Terminal (Applications > Utilities).
- Type these commands one by one:textcd /Library/Preferences/SystemConfiguration/ sudo rm com.apple.airport.preferences.plist sudo rm NetworkInterfaces.plist sudo rm com.apple.network.identification.plist
- Enter your password when prompted (it will not show while typing).
- Restart your Mac.
After restart, you will need to re‑enter Wi‑Fi passwords. Then test your speed. This fix alone resolves mac wifi slow after update for many users. For a detailed walkthrough, see our reset macOS network settings guide (cluster post #10).
Fix 2: Turn Off Bluetooth (2.4 GHz Interference)
If your Mac uses the 2.4 GHz Wi‑Fi band, Bluetooth devices can cause severe interference. This slows speeds dramatically. A macOS update may have re‑enabled Bluetooth or changed its power management. Therefore, testing this is worthwhile.
Test:
Turn off Bluetooth completely. Go to System Settings > Bluetooth and toggle it Off. Then test Wi‑Fi speed. If speed improves, interference is the culprit.
Permanent solutions:
- Switch to 5 GHz Wi‑Fi instead (see Fix 7).
- Reduce the number of active Bluetooth devices.
- Keep Bluetooth on but move your Mac and router farther away from Bluetooth peripherals.
For more on Bluetooth conflicts, see our Mac VPN connection issues (cluster post #7). That guide also covers how interference affects VPN stability.
Fix 3: Disable AWDL (AirDrop Scanning)
Apple Wireless Direct Link (AWDL) powers AirDrop and Sidecar. After a macOS update, AWDL may become more aggressive. It scans for nearby devices frequently, causing latency spikes and speed drops. Consequently, your Wi‑Feels slow even though the signal is strong.
Temporary test (disables until next reboot):
Open Terminal and type: sudo ifconfig awdl0 down
Then test your speed. If speed improves, AWDL is the culprit.
Permanent fix for that network:
Change your router’s 5 GHz channel to 149 or higher. AWDL primarily scans channels 44 and 149. By moving your network to a different channel, you reduce contention. For a complete AWDL guide, see our Mac Wi‑Fi signal strength guide (cluster post #1) and pillar post Fix 5.
Fix 4: Change DNS Servers to Public Options
A macOS update may have reset your DNS settings to your ISP’s default. ISP DNS servers are often slow. Switching to public DNS can restore speed.
Recommended public DNS servers:
- Google: 8.8.8.8 and 8.8.4.4
- Cloudflare: 1.1.1.1 and 1.0.0.1
How to change:
- System Settings > Wi‑Fi > Details (ⓘ) next to your network.
- Click DNS.
- Add the new servers using the + button. Remove any slow ones.
- Click OK.
Test speed immediately. If improved, keep these DNS servers. For more on DNS, see our Mac Wi‑Fi on no internet (cluster post #12). That post covers how DNS also affects connectivity.
Fix 5: Renew DHCP Lease
Sometimes after an update, your Mac holds onto an old IP address that conflicts with the router. Renewing the DHCP lease forces a fresh IP. This is a quick and safe fix.
Steps:
- System Settings > Wi‑Fi > Details (ⓘ).
- Click the TCP/IP tab.
- Click Renew DHCP Lease.
- Wait 10 seconds, then test speed.
If your IP address was in the 169.254.x.x range (self‑assigned), this fix is critical. For more on DHCP, see our Mac Wi‑Fi vs Ethernet guide (cluster post #4).
Fix 6: Disable VPN and Content Filters
A macOS update may have enabled or re‑enabled VPN profiles, iCloud Private Relay, or content filters (parental controls, security software). These can dramatically slow Wi‑Fi. Therefore, checking them is essential.
Check Private Relay (iCloud+ feature):
Go to System Settings > Apple ID > iCloud > Private Relay. Turn it off temporarily.
Check third‑party VPNs:
Open System Settings > VPN. Disconnect any active VPN.
Check content filters (e.g., Little Snitch, antivirus):
Look in System Settings > Network > Filters. Disable any third‑party filters.
After disabling these features, restart your Mac and test speed. If speed returns, re‑enable them one by one to find the culprit. For VPN troubleshooting, see our Mac VPN connection issues guide (cluster post #7).
Fix 7: Check Router 5 GHz Channel and Firmware
A macOS update may have changed how your Mac interacts with certain 5 GHz channels. This is especially true for Wi‑Fi 6E Macs. Consequently, adjusting your router settings can help.
Check your current band:
Option‑click the Wi‑Fi icon. Look for Channel (e.g., “36, 80 MHz” or “149, 160 MHz”). If you are on a DFS channel (52‑144), try switching to a non‑DFS channel (149+).
How to change router channel:
- Log into your router (192.168.1.1 or similar).
- Find wireless settings.
- Set the 5 GHz channel manually to 149, 153, 157, or 161.
- Save and reboot the router.
Additionally, update your router firmware. Check your router manufacturer’s website or admin panel for updates. Outdated firmware can cause slow speeds after macOS updates. For Wi‑Fi 6E specific issues, see our Mac Wi‑Fi 6E issues guide (cluster post #6).
Frequently Asked Questions
Q: Why is my Wi‑Fi slow only after a major macOS upgrade (e.g., from 26 to 27)?
Major updates often reset network preferences and enable new features. The fixes above (especially Fix 1 and Fix 6) are designed for this scenario.
Q: I updated macOS, and now my Wi‑Fi speed dropped from 300 Mbps to 30 Mbps. What gives?
This often points to AWDL interference or DNS corruption. Try Fix 3 (disable AWDL) and Fix 4 (change DNS). Also check that you are on 5 GHz, not 2.4 GHz.
Q: Does Apple’s Private Relay slow down Wi‑Fi?
Yes, sometimes significantly. Private Relay routes your traffic through two separate servers, which adds latency and reduces speed. Disable it (Fix 6) to test.
Q: My speed is slow only on battery power but fine when plugged in.
That is power management. Go to System Settings > Battery > Options and disable Low Power Mode or set it to Only on battery. Also ensure Wake for network access is enabled.
Q: I tried everything, and my Wi‑Fi is still slow after update. What next?
Run Wireless Diagnostics (Option‑click Wi‑Fi icon > Open Wireless Diagnostics). It may detect issues like channel congestion or interference. If nothing helps, consider that the update may have a bug. Check Apple’s discussion forums for others with the same issue; a subsequent point update may fix it.
Q: Will resetting network settings (Fix 1) delete my saved Wi‑Fi passwords?
Yes. Make sure you have your passwords written down before performing Fix 1. This is a last resort.