Comment 3 for bug 395919

I also have this issue on a Macbook Pro 5,5 running Ubuntu 10.04. NM will try to connect for 5 minutes (with the laptop sitting right next to the wireless router), and will either re-prompt me for the WPA2 password a dozen times, or just give up and say it was disconnected (even though it was never connected in the first place). Only about 1 in 12 times it will connect successfully. This essentially makes wireless networking unusuable for me using NM. I've had no issues at all connecting to the same wireless router with other machines (Ubuntu desktop using a USB wireless dongle, and an Android phone), so the issue doesn't seem to be on the router's side.

The only workaround I've found is to remove ALL network-manager packages, and install the equivalent Wicd packages, which is able to connect immediately. It would be nice to have similar functionality with NM, since it has a more intuitive interface than Wicd IMHO.