act "unable to find image / pull access denied" for the runner image

By Kaveh Alemi·Latchkey

act pulls the container image mapped to your runner label. This error means the image name or tag does not exist, or the registry refused the pull, so act has no image to start the job in.

What this error means

act prints "Unable to find image 'catthehacker/ubuntu:act-latest' locally", then a pull error such as "pull access denied" or "manifest unknown".

act

Unable to find image 'catthehacker/ubuntu:act-lastest' locally
docker: Error response from daemon: pull access denied for catthehacker/ubuntu,
repository does not exist or may require 'docker login'.

Common causes

A typo in the image name or tag

A misspelled repository or a nonexistent tag (like act-lastest) makes the registry return "repository does not exist" or "manifest unknown".

A private or rate-limited registry

The image is private, or Docker Hub rate-limited the anonymous pull, so the daemon is denied.

How to fix it

Use a correct, existing image tag

Map to a published tag such as catthehacker/ubuntu:act-latest and fix any typo.

Terminal

act -P ubuntu-latest=catthehacker/ubuntu:act-latest

Authenticate or pull ahead of time

Run docker login if the image is private or you are rate-limited.
Pre-pull the image with docker pull to confirm it resolves.
Re-run act once the pull succeeds.

Terminal

docker login
docker pull catthehacker/ubuntu:act-latest

How to prevent it

Pin exact image tags in .actrc and copy them, do not retype.
Authenticate to the registry before running act on private images.
Pre-pull runner images in CI-of-CI setups to avoid rate limits.

Frequently asked questions

What causes ""pull access denied" for runner image"?

A misspelled repository or a nonexistent tag (like act-lastest) makes the registry return "repository does not exist" or "manifest unknown".

How do I fix "pull access denied" for runner image?

Map to a published tag such as catthehacker/ubuntu:act-latest and fix any typo.