Hello when I run the command sudo add-apt-repository ppa:libretro/stable I get the message Updating from such a repository can’t be done securely, and is therefore disabled by default. I have researched online but still do not know what to do. Retroarch does not list any cores in the download section of the app which I believe is related to this issue. -Thanks
Are you installing something more than “retroarch”?
What do you use? First, verify that it is supported in your distro
Then eliminate the repository:
sudo ppa-purge ppa:libretro/stable -y; sudo apt purge retroarch -y
Reinstall the PPA, keep in mind that you are going to ask for verification, you have to press the Enter key:
sudo add-apt-repository ppa:libretro/stable
Install Retroarch alone:
sudo apt install retroarch -y
You need to update “Core Info Files” before, to see the list of cores.