Mountain Lion no Wifi after wake from sleep

Hey guys,

I have the following problem:

after I wake my 17" MacBook Pro 8,3 (early 2011) from sleep by opening the lid, it starts searching for a WiFi network to join. It will just keep searching and searching, without ever finding anything. When I try to click on the WiFi icon in the menubar I get the beachball, also the System Preferences are affected by this crash - I can't go to "Network", it also beachballs. The only way out is a restart.

To prevent this from happening I can disable WiFi before putting my mac to sleep, but that's quite inconvenient. I have disabled all Auto Proxies, tried to delete the known networks from both the Network pane and the Keychain.

😟