This is a problem and solution. When we had this problem we found no help online. When we phoned Plusnet the tech support person we spoke to had never come across this problem but he asked a colleague and he knew the fix. I thought I would post that fix in case it is useful to anyone else.

Basically when our MacBook first tried to connect to our new Plusnet router over the WiFi it hung and we had to do a hard reset. On reboot it hung again, then next reboot same again. I disabled the WiFi from the router using my Windows laptop via the router’s gateway web page and we could boot the mac again. Then I turned on the WiFi and a few seconds later the Mac hung.

We repeated this procedure but with the network menu dropped down and it seemed like the first instance of “Airport: Looking for networks” after the WiFi was switched on caused the hang.

The fix was as follows:

1) Turn off the WiFi, either via the router gateway or just turn off the router.
2) Turn on your Mac
3) Click the wifi symbol and select Open Network Preferences
4) Make sure AirPort is selected and pres the Advanced… button
5) select the TCP/IP tab
6) Under configure IPv6, select Off.
7) press OK then Apply and close down the Network window, then reboot.
Cool While rebooting you should be able to turn the WiFi back on.
9) Hopefully you should now be able to enjoy your WiFi 🙂
Hope this helps someone. If it is of any interest we are running Mac OS X Snow Leopard and the router was a SagemCom 2704N.