No Wi-Fi Adapter Found Error On Pop-OS

Have you already read this? https://support.system76.com/articles/wireless

The operating system cannot find an usable wireless network interface in your laptop. Possible reasons:

1.) There might be no wireless network interface at all (this might still be possible in very old or very cheap laptop models), or the wireless network interface is faulty. Have you used the laptop with any other OS and had the wireless network interface working with that OS?

2.) Your laptop might include a physical switch to disable all radio transmitters, and the switch might be currently in the "disable" position. Such a switch might also be implemented within the ACPI firmware to recognize a particular keystroke on the laptop's internal keyboard. Read the hardware documentation of your laptop to find out if there is a particular switch or key that can be used to disable Wi-Fi and Bluetooth, and try it.

3.) The wireless network interface might not be functional because it requires a firmware package that is currently not installed. This could be fixed by using another computer to download the correct firmware file to a USB stick and then copying the firmware file to the appropriate directory under /lib/firmware/ on your laptop.

4.) The wireless network interface could be of such a new type that the default kernel of your Linux distribution does not yet have a driver for it as standard. Your Linux distribution might have extra drivers for such cases packaged as DKMS packages, but first the wireless chip needs to be identified so that the correct package can be identified.

First, you'll need to identify your laptop model and the wireless network chip in it, if one exists. Please edit your question to add in the results of the following commands:

cat /sys/class/dmi/id/product_name 

The command above should identify your laptop model.

lspci -nn 

This command should produce a listing of all PCI/PCIe hardware devices in your laptop. If you can recognize the line that refers to the wireless network interface, you can just post that line only. Please don't leave out any numbers or codes on that line: they can be useful in identifying the type of the wireless network chip as exactly as possible.

lsusb 

This command should respectively produce a listing of all USB-connected hardware devices in your laptop. (Yes, a hardware device can be internal to the laptop and still be connected by USB.)

The lspci -nn and lsusb commands will identify the hardware devices by using the standard interfaces of the respective hardware buses only, and so they can provide basic information on devices that have no driver installed yet.

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In the comments you mentioned a PCI vendor:device ID of 10ec:c821. That would be a Realtek RTL8821CE. Since you are - also according to your comments - using kernel version 5.8, this is case #4.

The in-kernel driver rtw88 would otherwise support RTL8821 series of wireless chips, but in kernel 5.8 it does not support RTL8821CE yet. The support was apparently added in the 5.9 kernel series, so it's a very near miss.

There is a third-party repository that has a working driver, but since it's in source code form, you would need to build it for your kernel. That requires installing a number of packages and running a number of steps. The instructions (for Ubuntu, but should be also applicable for Pop) can be found here.

In a nutshell, the steps to install the driver are:

sudo apt-get update sudo apt install git build-essential dkms git clone https://github.com/tomaspinho/rtl8821ce cd rtl8821ce chmod +x dkms-install.sh chmod +x dkms-remove.sh sudo ./dkms-install.sh 

Once your system gets updated to use kernel version 5.10 or later, you should no longer need this third-party driver, and eventually it will be too old to be used with new kernel versions. At that point, you can remove it with cd rtl8821ce; sudo ./dkms-remove.sh.

If your system uses UEFI, you will need to either disable Secure Boot or create and install a MOK key (Machine Owner's Key) or take full control of your system's Secure Boot keys before installing the driver, or else you won't be able to use kernel modules you've built yourself. Of these options, disabling Secure Boot or creating a MOK are usually the easiest.

As far as I know, the MOK creation process can be started in Debian/Ubuntu/Pop_OS with:

sudo update-secureboot-policy 

It will ask if you wish to disable Secure Boot, or create a MOK. When you choose the creation of a MOK, it will require you to set a one-time password, which you will need to enter the next time you reboot the system.

(The MOK set-up process can only happen at boot time, when the MOK manager program can be reasonably certain that its inputs are not subverted by an intruder.)

In case it is like in the following image:

you just really need it turn on using a slider above right. In the middle it says "Wi-Fi Unavailable", then the next to the right is the slider, vertical three dots, "-" for minimize window, "x" for close window.