✓ Solved

After updating from 22.04 to 24.04. An error occurs when running apt update.

After I updated from 22.04 to 24.04, running apt update gives me error N: Missing Signed-By in the sources.list(5) entry for 'http://mirrors.linode.com/ubuntu'.

According to the search, I have to edit /etc/apt/sources.list.d/ubuntu.sources.

However, after edii /etc/apt/sources.list.d/ubuntu.sources to the following, I still get the same error. How can I fix it.

Types: deb
URIs: http://security.ubuntu.com/ubuntu
Suites: noble-security
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

Types: deb
URIs: http://mirrors.linode.com/ubuntu
Suites: noble-security
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

Thanks!

2 Replies

✓ Best Answer

During my testing, I upgraded a fresh Ubuntu 22.04 LTS >> 24.04 LTS and rebooted, after which point I received a similar error. This ServerFault post that suggests although you'll likely be using our mirrors, Ubuntu's signed key needs to be added manually to the ubuntu.sources file.

I replicated the solution by entering the following commands:

echo "Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg" >> /etc/apt/sources.list.d/third-party.sources
apt update

It works. Thank you!

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