Have you upgraded your Mac to OS X Yosemite yet? If you haven't already, then you might to hold off that plan because a lot of users are complaining about a bug/glitch on the latest version of the OS which causes the Wi-Fi to either disconnect every so often or won't connect to a wireless network at all. Meanwhile, some users who were able to connect to their Wi-Fi network even after upgrading to OS X Yosemite are faced with unstable and, most of the time, unusable internet connection on their Mac.