If you dual boot your Laptop or PC with any other OS and you restart Ubuntu then it will show Error[Wireless connection is not present or no network devices are available]. This issue may happen also due to the installations of unwanted software in Ubuntu.
Problem: Wireless network (Wi-Fi) option is not available.
Follow the below steps to get back the Wi-Fi option on Ubuntu
Note: First connect a wired device to your laptop so that you can use internet services to follow further steps.
Step 1: Open Terminal using Ctrl+Alt+T.
Step 2: Update system packages using the following command.
sudo apt-get update
Step 3: Install the required packages using the following command.
sudo apt install git build-essential dkms
Step 4: Clone the Realtek RTL8821CE Driver using the following command.
git clone https://github.com/tomaspinho/rtl8821ce
Step 5: Move to the repository directory using the following command.
cd rtl8821ce
Step 6: Use the following command to make the script of dkms-installation executable.
chmod +x dkms-install.sh
Step 7: Make the dkms-remove script executable.
chmod +x dkms-remove.sh
Step 8: Execute the installation script using the below-mentioned command.
sudo ./dkms-install.sh
After doing these steps restart your PC, and now you can see that the wireless network option is available.