如何解决“存储库‘cdrom://Ubuntu 20.04.2.0 LTS _Focal Fossa_ - Release amd64 (20210209.1) focus Release’没有发布文件”？

Question

$ sudo apt update
E: The repository 'cdrom://Ubuntu 20.04.2.0 LTS _Focal Fossa_ - Release amd64 (20210209.1) focal Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

Answer 1

打开软件和更新，在 Ubuntu 软件选项卡中，取消选中可从 CD-ROM/DVD 安装下的 CDROM with Ubuntu 20.04 'Focal Fossa'