Macbook Air mid 2013 with Mavericks stopped connecting to familiar wifi after 10.9.4 update I recently installed update 10.9.4, which was recommended for all Mavericks users. My wifi was working fine beforehand and now won't connect to familiar networks. Ironic much? The 10.9.4 update was supposed to fix wifi problems for Mavericks!

I have tried various troubleshooting approaches and nothing works. My mac is able to see the network but not connect to it. When I try, it just says "The network _____ could not be joined" and then gives me the option to run diagnostics, which does not help. I've tried resetting the SMC and PRAM, deleting the contents of the system config folder, and of course have restarted the machine several times. I've deleted the bluetooth config file, deleted and re-added the wifi in network preferences and renewed the DHCP lease. I'm afraid I'm out of ideas.
I would try to manually connect to network to see if that works.

Here are the steps how to do that using Terminal by copy/paste following:

Turn On

networksetup -setairportpower en0 on


Find

/System/Library/PrivateFrameworks/Apple80211.framework/Versions/A/Resources/airport scan


Connect

networksetup -setairportnetwork en0 WIFI_SSID_I_WANT_TO_JOIN WIFI_PASSWORD