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You may find these troubleshooting steps helpful if your MacBook Pro is not connecting to your Wi-Fi network after it wakes from sleep:
After restarting or waking from sleep, my computer might not connect to the Internet
Use these steps if your computer does not automatically connect to your desired Wi-Fi network.
1. Check your TCP/IP settings in the Network pane of the System Preferences. Click the "Renew DHCP lease" button
- Choose System Preferences from the Apple menu.
- Choose Network from the View menu.
- Select Wi-Fi, then click the Advanced button in the lower-left hand corner of the screen.
- Click the TCP/IP tab from the top of the screen.
- Click the "Renew DHCP lease" button.
- Select each network and click the minus sign to remove those networks from your Preferred Networks list.
- Click OK and close the Network preferences.
- Open Keychain Access from /Applications/Utilities.
- Remove your AirPort network passwords from the login keychain: Select the "login" keychain from the Keychain sidebar. Click the "Kind" column to order the list of keychain items by their type. Remove all entries of the kind: "AirPort network password".
- Remove your AirPort network passwords from the System keychain: Select the "System" keychain from the Keychain sidebar. Click the "Kind" column to order the list of keychain items by their type. Remove all entries of the kind: "AirPort network password".
Note: The above steps will remove your Wi-Fi network passwords. If you do not know them, or if your network does not use passwords to restrict access, you should contact your network administrator.
4. Restart your computer.
5. Join your Wi-Fi network. You will need to enter your password for your network again if it requires one.
You can find these steps with additional screenshots in the "Symptom: The network connection drops unexpectedly" section of this article:
Wi-Fi: How to troubleshoot Wi-Fi connectivity