Wifi Networks "Device not ready" error solve in Linux

While working on my Ubuntu system, one day my Wi-Fi stopped working. When I click top right button, WiFi Networks shows error message shows Device not ready.

After digging deeper, I came to know this error caused mostly due to wifi adapter issue. Here I have found such scenario when you get this error, then how to resolve it.

First of try to restart NetworkManager. This is the most common you surely overcome the issue. You can restart the NetworkManager with the bellow command:

sudo service network-manager restart

If you have recently installed WICD network manager, then first disable WICD with bellow command:

sudo service wicd stop

And then restart the network manager with the same command.

sudo service network-manager restart

If you have removed wicd package, then you have to also remove unused package that comes with wicd. Run bellow command to remove unused packages.

sudo apt-get autoremove

If the above method doesn't work, then run bellow command:

lsmod | grep acer

There will be several entries appear in the Terminal. If acer_wmi is in the list, then enter:

echo "blacklist acer_wmi" | sudo tee -a /etc/modprobe.d/blacklist.conf

Then reboot the computer and check if this works.

If there is still issue persist, then check wifi adapter is physically connected.

iwconfig

Or check if wifi is blocked or not:

rfkill

If wifi is blocked then unblock it:

rfkill unblock wifi && rfkill list all

There may be missing firmware for the wifi device. To fix this issue, run bellow comand and install firmware for Wifi.

cd /lib/firmware/rtlwifi
sudo wget https://github.com/lwfinger/rtlwifi_new/raw/extended/firmware/rtlwifi/rtl8723defw.bin

Then reboot the system.