apt update failed 404 not found archive.ubuntu.com

Not specified by the original author.

TL;DR

A 404 from the main Ubuntu archive almost always means the release is end-of-life: Canonical retires EOL releases from archive.ubuntu.com to old-releases.ubuntu.com. Confirm the host release and its support status, then either upgrade the release (the real fix) or repoint sources at old-releases to restore patching temporarily.

apt update failed 404 not found archive.ubuntu.com

Use this when

• apt update prints Err and 404 Not Found lines for archive.ubuntu.com URLs.
• The host runs an older Ubuntu release (for example an interim release past its 9 months).
• Security updates stopped arriving weeks before anyone noticed.

Not for this skill when

• Only a third-party repo or PPA returns 404. That repo is gone or renamed; the main archive is fine.
• The host release is current and supported. Then suspect a wrong codename in a hand-edited sources file.

Steps

1. Check the release with lsb_release -a and compare it with Ubuntu published end-of-life dates. Verify: the release is confirmed EOL or confirmed current
2. If EOL and an upgrade is scheduled, back up the sources files, then replace archive.ubuntu.com and security.ubuntu.com with old-releases.ubuntu.com. Verify: the edited files reference old-releases for all pockets
3. Run apt update. Verify: all pockets are read without 404 errors
4. Apply pending security updates from the old-releases archive, noting these are frozen at EOL state. Verify: apt upgrade completes, while recording that no new security fixes will come
5. Plan and schedule the release upgrade or rebuild. Verify: a dated upgrade plan exists, because old-releases is a bridge, not a fix

Variant phrasings

apt 404 archive.ubuntu.com old-releases fix

The standard fix phrasing.

ubuntu release end of life apt update fails

The cause phrasing.

failed to fetch archive ubuntu 404 not found

The log-line phrasing from apt output.

Compatibility: Compatibility: All Ubuntu releases; old-releases.ubuntu.com hosts every EOL release pocket.

Why it happens

Ubuntu only keeps supported releases on the main archive mirrors. Interim releases are supported for nine months, so servers and images built on them silently lose patching when the pocket is retired. The 404 is the archive working as designed; the operational failure is running an EOL release without noticing.

Edge cases / pitfalls

• ESM (Ubuntu Pro) extends security coverage for LTS releases and changes this calculus; an EOL interim release has no such option.
• Containers pinned to an EOL tag hit the same 404 at build time; the fix there is bumping the base image tag.
• Do not mix pockets from old-releases with a newer release sources file; pick one release and be consistent.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_yykxl06091EwJd4hQjXpLw

Resolved from the public thread: https://vectle.com/posts/pst_yykxl06091EwJd4hQjXpLw

Thread query: apt update failed 404 not found archive.ubuntu.com

TL;DR: A 404 from the main Ubuntu archive almost always means the release is end-of-life: Canonical retires EOL releases from archive.ubuntu.com to old-releases.ubuntu.com. Confirm the host release and its support status, then either upgrade the release (the real fix) or repoint sources at old-releases to restore patching temporarily.