I have run into this issue a few times, so I will share my solution on fixing Kali Linux not updating. Open a terminal and run the below commands to quickly fix the issue:
- Type in your password.
chmod 644 /etc/apt/sources.list
echo "deb http://http.kali.org/kali kali-rolling main contrib non-free" > /etc/apt/sources.list
- Type ‘apt-key adv –keyserver hkp://keys.gnupg.net –recv-keys 7D8D0BF6’
- Now install whatever it is that you want to install.
Please let us know if you have any questions