I've installed a Wi-Fi access point and the signal overlaps with the Wi-Fi signal of the access point installed in the router. The access points have the same SSID and password.
This new installation seems to have confused the Mac of one of my housemates. It no longer connects automatically to the network but requires that you manually select the Wi-Fi network and connect. It does have the connect automatically option checked for the SSID of the network.
I would like to get answers/suggestions on what might be the problem on the conceptual level rather than how to fix it in OS X, and if it's possible to avoid these issues by a different access point setup?