trivy: "failed to analyze layer: layer not found" after the registry GC pruned blobs mid-scan

TL;DR

The registry's garbage collection deleted image blobs while trivy was reading them, so the manifest now points at layers that no longer exist. The image is half-deleted, not corrupt. Re-push the image so every referenced blob exists again, then rescan. Afterward, keep GC and scan windows from overlapping.

The query

trivy: "failed to analyze layer: layer not found" after the registry GC pruned blobs mid-scan

Use this when

• trivy fails with "failed to analyze layer: layer not found" on an image that scanned fine before
• A registry GC job ran recently (check the registry logs or job history)
• Pulling the image also fails or warns about missing blobs

Not for

• "unexpected EOF" mid-pull on a flaky network (transient, retry the pull)
• Corrupt layers in a local build cache (rebuild locally)
• "manifest unknown" errors (the tag or digest reference itself is wrong)

Steps

1. Confirm blobs are actually gone

crane manifest [registry]/[image]:[tag] | head -40

Expected output: the manifest lists layer digests. Then check whether the registry still serves one of those blobs; a 404 on the blob confirms GC pruned it.

2. Re-push the image from a good copy

Push from the CI artifact store or rebuild and push, so every blob the manifest references exists in the registry again.

docker push [registry]/[image]:[tag]

Expected output: the push completes and the registry reports the blobs as mounted or uploaded.

3. Rescan the repaired image

trivy image [registry]/[image]:[tag]

Expected output: the layer analysis completes and the scan reports findings instead of the layer error.

4. Separate GC from scan windows

Schedule registry garbage collection in a window where no scans or deployments run, or make GC operate only on untagged manifests. Verify: the next GC run completes and a scan immediately after it still passes.

5. Prefer immutable references for scanning

Scan by digest (image at digest sha256:...) rather than by tag in scheduled jobs, so a tag moving mid-scan cannot produce a half-read image. Verify: the scan job logs the digest it scanned.

Variant phrasings

trivy layer not found after registry garbage collection

The same failure described from the cause side.

failed to analyze layer layer not found trivy

The short error form, for exact-match searchers.

Compatibility: trivy image scans against any OCI registry that runs garbage collection (Harbor, distribution, cloud registries).

Why it happens

A container image is a manifest plus a set of content-addressed blobs. Garbage collection deletes blobs no longer referenced by any manifest it knows about, but a scan in flight may be reading a manifest whose blobs get pruned between the manifest fetch and the layer fetch. Trivy then asks for a layer digest the registry no longer has, and the scan fails.

Edge cases / pitfalls

• Multi-arch images are extra fragile here: GC can prune one platform's blobs while the manifest list still references them, failing only some platform scans.
• If the only copy of the image was the registry copy, you must rebuild from source. There is no way to resurrect pruned blobs.
• Some registries GC untagged manifests aggressively. Pushing the same tag again does not protect the old blobs; the digest you scanned is what matters.
• A rescan that passes after re-push does not prove the image is unchanged. Compare digests before and after if the image is a release artifact.

Provenance

Resolved from the public thread: https://vectle.com/posts/pstYv6cyr0zQWgXQ00yBXUFQ