Macbook Pro running mavericks loses wifi connection everytime I close the lid.

This seems to work for me:

1. Open System Preferences>Network>

2. In the left hand side of the Network window remove Bluetooth PAN by selecting it and then clicking "-" at the bottom.

So far it's worked for me. I tried closing lid and letting the computer go into Energy Saver Mode. And when I logged back in my wifi connection was still good. However, I'm running OS X El Capitan.

Hello there, Whytey1966.

The following Knowledge Base article provides some great information and recommendations for your issue:

Wi-Fi: How to troubleshoot Wi-Fi connectivity

http://support.apple.com/kb/HT4628

In particular:

Symptom: After restarting or waking from sleep, my computer might not connect to the Internet

• After waking from sleep or starting up, your computer may not show that it is connected to a Wi-Fi network.
• After start or wake, your computer may indicate that it is connected to a network, but does not connect to the Internet.

Solution

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

1. Choose System Preferences from the Apple menu.
2. Choose Network from the View menu.
3. Select Wi-Fi, then click the Advanced button in the lower-left hand corner of the screen.
4. Click the TCP/IP tab from the top of the screen.
5. Click the "Renew DHCP lease" button.

2. Select the Wi-Fi tab and view your Preferred Networks list.

1. Select each network and click the minus ( - ) sign to remove those networks from your Preferred Networks list.
2. Click OK and close the Network preferences.

3. Remove your stored network passwords using the Keychain Access Utility.

1. Open Keychain Access from /Applications/Utilities. Your window will look like this:
   
2. 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".
3. 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.

Thanks for reaching out to Apple Support Communities.

Cheers,

Pedro.

Key issue here is that the "Remember Networks..." option as seen in Step 2 above be selected. That will cause the Wi-Fi network parameters such as the SSID and any required password to be stored on the Mac and it will be able to rejoin automatically in the future.

Seems to be my problem also.

My BacBook Air after upgrading to Mavericks won't connect to Wi-Fi network automatically after returning from sleep. Every time I have to choose my network manually from the list.

On previous OS X version (Mountain Lion) all went just fine as it should be.

My routers has only 2,4 GHz. Tried a lot of solutions from the Internet, nothing helps. It's definitely OS X software problem, I hope Apple will find a way to fix that.

Just found solution in another thread that helped to me:

I had the same issue on my mac mini, not connecting to wifi after sleep, after speaking to a senior tech advisor at apple today problem has been resolved, it is a known problem that Bluetooth settings are interfering with wifi reconnection, we deleted several files that didn't fix the issue then at last attempt this fixed it, In Finder go to Computer/Mac HDD/Library/Preferences and delete file com.apple.Bluetooth.plist, reboot and back to normal.

It really solved my problem so far.

Same here! Turned off Bluetooth and now my Macbook Air automatically rejoins my home wifi. (It was only this one network it had a problem with). Before turning off Bluetooth I had to turn wifi OFF then ON again... everytime. Very annoying.

This also was the only thing that made this problem disappear. Thank you!

Yes turning off Bluetooth solves the issue, but Apple really needs to fix the software problem that they created with this OS release. It is completely unacceptable to tell customers to "just turn off your Bluetooth" to get your internet to come back after the device has been put to sleep. For one thing, with prior levels of OSx this wasn't necessary. Another point, what about your Bluetooth devices (keyboards, speakers)? Oops, did you forget about that Apple? come on, you introduced the bug with this OSx release, just admit it, and fix it.

I have the same problem but I cannot turn off the bluetooth because I al using the Apple BT mouse.

It seems like Apple fixed some related stuff in the latest OS X 10.9.4 update:

Fixes an issue that prevented some Macs from automatically connecting to known Wi-Fi networks

Please somebody report if the topic's issue gone after installing the 10.9.4 update.

re: 10.9.4 update fixing the problem.

Did not fix my MacBook Pro. I'm at 10.9.4 and after wake from sleep - Safari shows not connected to internet message. If I refresh the page - it then re-connects OK.