The Repository 'https //download.docker.com/linux/ubuntu Focal Inrelease' Is Not Signed Exclusive May 2026

First, remove any existing Docker repository files to avoid conflicts. sudo rm -f /etc/apt/sources.list.d/docker.list Use code with caution. 2. Install Prerequisites

Older tutorials used apt-key add , which is now deprecated in Ubuntu 20.04 (Focal Fossa) and later. Modern systems expect keys to be stored in /etc/apt/keyrings/ .

Ensure you have the necessary tools to handle HTTPS and GPG keys. First, remove any existing Docker repository files to

To resolve this, you must manually download the Docker GPG key and update your repository source file to point to it correctly. 1. Clean Up Old Configurations

The following signatures couldn't be verified because the public key is not available - multi try Install Prerequisites Older tutorials used apt-key add ,

sudo apt-get update sudo apt-get install -y ca-certificates curl gnupg lsb-release Use code with caution. 3. Add the Official GPG Key Create a dedicated keyring directory and download the key.

The most common cause is that the public key (often identified as 7EA0A9C3F273FCD8 ) has not been added to your system's keyring. To resolve this, you must manually download the

The error message typically occurs because the GPG key used to verify Docker 's official repository is missing, expired, or stored in a deprecated format. This security feature prevents APT from downloading packages that cannot be authenticated. Why This Error Occurs

Occasionally, a "not signed" error during a docker build can actually be caused by insufficient disk space in the Docker environment, which prevents the signature file from being processed correctly. How to Fix the GPG Error