After update, i have problems with wifi

Back up all data, then reinstall the OS. You don't need to erase the startup volume, and you won't need your backup unless something goes wrong. If your Mac was upgraded from an older version of OS X, you’ll need the Apple ID and password you used to upgrade.

If you installed the Java runtime distributed by Apple and still need it, you'll have to reinstall it.

I have the same problem. It will search and search for networks.

If I remove the wifi under network and reboot. Add the wifi back under network then my wifi will work for that session. If I reboot it reverts back to search for networks continuously.

This happend right after the 10.8.5 update.

I also read to try and install the 10.8.5 combo update, wifi worked durring the frist reboot but then reverted back to the way it was after.

Information.

Troubleshooting Wi-Fi connection issues - MacBook Air (Mid 2013)

Troubleshooting Wi-Fi issues in OS X

Wireless Connection Problems - Fix

Wireless Connection Problems - Fix (2)

Wireless Connection Problems - Fix (3)

Wireless Connection Problems - Fix (4)

Wireless Diagnostics - About

Can you ping your router on wake ? If yes, can you ping 8.8.8.8 ? Try deleting the network entry from your preferred network list and re-joining the network and check.