我该如何解决“存储库‘cdrom://Ubuntu 20.04.2.0 LTS _Focal Fossa_ - Release amd64 (20210209.1) focal Release’没有 Release 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“带有 Ubuntu 20.04‘Focal Fossa’的 Cdrom”