I'm sure this has been covered, I've been using PI's for three years, and I have NEVER been able to get WIFI running.
Currently I'm setting up a PI Zero, my Interfaces is standard and checks out:
iface lo inet loopback
iface eth0 inet dhcp
iface wlan0 dhcp
I can see the setup in ifconfig (it doesn't show it's running), and if I do a wlist I can see my network and everyone else in the neighborhood. However if I run ifup wlan0, I eventually get the 'No DHCP offers recieved'.
I reset the password on the router (it's an apple AirPort Express) just to be sure...
The hard part is that I can't connect to the device to do screen caps or anything else , it would be nice to run it headless, but I need network for that. So it's a small monitor and keyboard to figure all this out...
Thanks for any help...
This is VERY frustrating...