Mac Won't Connect to Wi-Fi

🔍 Step 1: Identify the Problem Type

• No networks visible at all: Wi-Fi hardware issue or Wi-Fi turned off
• Network visible but won't connect: Wrong password, router issue, or IP conflict
• Connects but no internet ("connected, no internet"): DNS issue, ISP problem, or DHCP failure
• Only this Mac has the issue (other devices fine): Mac-specific software or hardware problem
• All devices have the issue: Router or ISP problem — restart router first

📶 Step 2: Restart Router and Mac

1. Unplug your router/modem from power — wait 30 seconds — plug back in
2. Wait 2 minutes for it to fully reconnect to your ISP
3. Turn Wi-Fi off on your Mac (System Settings → Wi-Fi → toggle off), wait 10 seconds, turn back on
4. Restart your Mac fully — Apple menu → Restart

This fixes the majority of Wi-Fi connection issues. A router that's been running for weeks can develop memory issues that cause erratic behavior for connected devices.

🗑️ Step 3: Forget and Rejoin the Network

1. System Settings → Wi-Fi
2. Click the ⓘ next to your network name
3. Click Forget This Network → confirm
4. Click on the network name again and re-enter the password

Saved network profiles can become corrupted — especially after a macOS update or router firmware change. Forgetting and rejoining rebuilds the profile from scratch.

🌐 Step 4: Change DNS Servers

"Connected but no internet" is almost always a DNS issue. Your ISP's DNS servers can fail or be slow without the connection appearing to drop:

1. System Settings → Wi-Fi → click ⓘ → Details → DNS
2. Click + and add: 8.8.8.8 (Google) or 1.1.1.1 (Cloudflare)
3. Click OK → Apply
4. Open Terminal and run: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

If websites start loading after changing DNS, your ISP's DNS servers were the problem. Keep the faster public DNS servers going forward.

🔄 Step 5: Renew DHCP Lease

IP address conflicts happen when two devices get the same address, or when the Mac's lease expires and it can't get a new one:

1. System Settings → Wi-Fi → ⓘ → Details → TCP/IP
2. Click Renew DHCP Lease
3. Wait 10 seconds, then test internet access

Alternatively, from Terminal: sudo ipconfig set en0 DHCP (replace en0 with your Wi-Fi interface if different — check with networksetup -listallhardwareports)

📁 Step 6: Delete Wi-Fi Preference Files

Corrupted preference files are a common cause of persistent Wi-Fi issues that survive basic fixes:

1. Open Finder → Go → Go to Folder (⇧⌘G)
2. Type: /Library/Preferences/SystemConfiguration/
3. Delete these files (move to Trash):
   • com.apple.airport.preferences.plist
   • com.apple.network.identification.plist
   • NetworkInterfaces.plist
   • preferences.plist
4. Restart your Mac — macOS recreates these files with clean defaults
5. Rejoin your Wi-Fi network

This is the nuclear option for software-based Wi-Fi issues. It clears all saved network configurations, so you'll need to re-enter passwords for all networks.

🔧 Step 7: Check for macOS Update

System Settings → General → Software Update. Wi-Fi driver bugs affecting specific Mac models are regularly patched. If Wi-Fi issues appeared after a macOS update, a subsequent point release often fixes it.

📊 Step 8: Check Wi-Fi Diagnostics

macOS includes a built-in Wi-Fi diagnostic tool:

1. Hold Option and click the Wi-Fi icon in the menu bar
2. Click Open Wireless Diagnostics
3. Follow the on-screen prompts — it scans for interference, signal quality, and configuration issues
4. Check the Summary at the end for specific problems identified

This is especially useful for intermittent drops — it captures diagnostics at the moment of the drop if you run it during the problem.