System Prefs freezes when joining to new wireless networks.

First, I apologize if this topic has already been covered, but I've searched for days and have found nothing. I have a 2012 MBP. Whenever I attempt to join to a new wireless network (one which is not already remembered) my System Prefs will hang (beach ball) for almost 10 minutes before I get an authentication prompt. I have a dual band router and this happens on both 2.4GHz and 5GHz. My router's security right now is set to WPA2-Personal AES. I've tried changing my router's channels. I've looked for updated firmware for my wireless adapter (none). Of course I've tried rebooting. I've also tried resetting my wireless settings by deleting some the related plist files in the library. I think that's all I've tried. Any help would be appreciated. Let me know if I you guys need any more information. Thanks.

Wow, 172 views and no comments yet? No questions, either? Has my laptop stumped everyone? Haha. I mean it could just be a hardware issue, but if that's the case I can't be the only one who's experienced this. It has to have at least been mentioned somewhere by someone. Any help is appreciated.

Not ignoring you but I have not heard of this so yeah you got me stumped.
Does it work ok on listed wireless connections or is it slow ?
Have you contacted Apple as it should still fall under warranty?

It connects just fine to remembered wireless networks. If they are "listed", as in the MBP picks up their SSID broadcast, it doesn't matter. My guess is the issue is related to some weird bug with authentication. I've seen some really strange solutions fix some seemingly unrelated issues. For instance, I was getting "ghost" prompts for saving or exporting files in certain programs. As in the window would be there but I couldn't see it. If I opened Expose I could see the menus from the prompts but couldn't select them. Turns out disabling file sync in iCloud cleared that up. Who knows what little setting hidden in a tiny corner somewhere could be causing this...

I assume you have ask to join selected in preferences.

Yes, that option is enabled.

I would take it in an Apple Store and let them look at it .

Which Mac do you have and what version of OS X are you running? Once you get past the wait, does it successfully connect to the new wireless network? Can you try going to a previously known network, make it forget it and go through the process of connecting to the now "new" network and see if the problem persists?

Can you boot into Safe Mode and see if the problem persists?

Good questions. I have 2012 MBP (non-retina). 10.8.5 Mac OS X. It will connect successfully after the wait, yes. Actually, I have tried forgetting a known network and trying to reconnect. Problem will persist in that case. I haven't tried safe mode. I will give that an attempt and let you know.

[SOLVED] Thanks to those who helped. I figured out the issue. Turns out it was caused by my keychain. The whole time I had a sneaking suspicion it was related to some sort of authentication issue. Because of another issue I ended up opening Keychain Access for the first time in a long long while. I was having trouble using the program, as it kept freezing. I finally was able to open keychain first aid (after waiting about 10 minutes for it to unfreeze) and found it was corrupted. I went ahead and deleted the entire keychain just to start fresh, though I probably could have repaired it and it would have been okay. The problem with keychain seemed similar to wireless so I then forgot one of my wireless networks and tried to reconnect anew and it worked immediately. Makes sense, since if it knows the network it knows where it is in the keychain and pulls up the authentication immediately. If it doesn't remember the network it will then search my whole keychain for the stored credentials, eventually running into the corruption and causing that massive delay for the password prompt.