I have just now re-installed the system while unticking the option "Download upgrades while installing" during the installation. And then proceeded to do "sudo apt install build-essential gcc g++" and it worked just fine. Then I did "sudo apt update ; sudo apt upgrade" and everything is working fine now.
So, it remains a mystery why it was possible to do a simple complete install resulting in build-essential not installable. Since I can't reproduce this anymore (I am not going to reinstall with the option "Download updates while installing") you can close the issue, if you wish. Or try reproducing it, but then "Download updates while installing" obviously depends on time, so whatever it was causing a few days ago it may or may not cause again... -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1920753 Title: Cannot install build-essential on fresh Ubuntu 20.04.2 installation To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/build-essential/+bug/1920753/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs