Problem :

Wi-Fi networks not detected anymore

What triggered it ?

My computer froze and I ended up having to restart it using the power switch. In case it could be relevant : it froze while I was using Calc, trying to drag and drop items (bug already filed in LibreOffice).

What have I attempted to solve it ?

I was under Kubuntu 13.10 when it happened, so I took this opportunity to reinstall the OS with Kubuntu 14.04 (no config files were kept), but it didn't solve it.

Current diagnosis :

When running "sudo iwlist wlan0 scan", "wlan0 No scan results" comes up.

The /var/lib/NetworkManager/NetworkManager.state shows :

  • NetworkingEnabled=true
  • WirelessEnabled=true
  • WWANEnabled=true
  • WimaxEnabled=true
  • WiMAXEnabled=true

What could I try ?


2 Answers 2


It was a hardware problem more than a software one : I ended up resetting the BIOS to the default settings, but doing this wasn't enough : unplugging the charger cable and removing the battery before restarting my computer was needed too.

Maybe if I had just tried removing the battery and charger, without resetting the BIOS fist, it would have been enough (since I can't remember having made any significant change on the BIOS before), but I tried the other way round.

This problem was triggered when my virtual memory got overloaded, so I guess it makes sense it was solved when no energy was given to my laptop to keep anything in it. Until now I thought rebooting a computer was enough to clean the memory, but apparently not.


Another reason for not detecting Wifi after new installations or such issues might be a problem with Network Adapter Drivers.

You can first check which Wifi Network Adapter is there in your PC.

lshw -C network 

Mine Wireless N/W adapter was Realtek rtl8723be. So I installed the drivers from :




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