BTW, forgot to specify in my original post, but the "Captive Network Assistant" is the program that pops up when you are trying to connect to a WiFi network that requires you going through a web-browser login page (similar to the popup that appears for closed WiFi networks on iDevices - iPads / iPhones / iPod Touch.
Indeed, Captive Network Assistant seems like a half-baked application at this point, lacking certain features provided in any browser. For instance, it should be able to store passwords (I know it tries to use previous login information in certain circumstances, but it fails on some network setups), and it should have a close button—indeed, Apple should be able to add it to the Force Quit window.
Until this is fixed, the safest way to kill the window is to open Activity Monitor (in /Applications/Utilities/), find the Captive Network Assistant process, and hit Quit Process in the toolbar.
I'm not in the circumstances right now to test this, but another possibility exists, which you could try at your own risk: If the CNA window crashes, try holding down shift-option-command-escape for a few seconds. This performs a no-questions-asked force-quit on the frontmost application, but I'm not sure at this point whether the system thinks CNA is enough of an application to be considered "frontmost." Hence the danger: it's possible the system could quit the application that's directly behind CNA, such as your browser.
I'm having a similar issue, and from some quick web searches I've done, many others are too. My university's wifi triggers the Captive Network Assistant to connect, but it just hangs while displaying nothing. Has Apple offered no solutions to this problem? The fact that my issue/response to this thread is four months after the original posting makes me doubtful that anything has been done. Is there any way to force my mac to use a another app (like a web broswer) to complete this authentication process?
I have similar issue with captive network assistant app on Lion which is conflicting with University wifi.
My Mac picks up University wifi, but then will not bring log in page on safari. It will bring the login page on firefox.
I do not know how to solve this issue. I am in contact with University IT people and Apple tech Support.
I am going to use my On Phone tech support till it last. I will keep all updated whats going on.
Aruba is wifi network provider in my University. Here is pdf file I found onlinehttp://www.arubanetworks.com/pdf/technology/Amigopod-CNA-bypass-AppNote.pdf