COPY failed: file not found
This error matches known, documented patterns with reliable solutions.
Quick Fix (Most Common Solution)
- Ensure file is in build context directory
- Check .dockerignore for exclusions
Seeing "COPY failed: file not found"? This error can be frustrating, but it's usually fixable. It typically affects your development workflow or system. Below you'll find clear, step-by-step solutions to resolve this issue.
What This Error Means
The file you are trying to copy into the image does not exist in the build context.
Frequently documented in developer and vendor support forums.
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Common Causes
- File outside build context
- Typo in file path
- File in .dockerignore
How to Fix
- Ensure file is in build context directory
- Check .dockerignore for exclusions
- Verify file path is correct
Last reviewed: June 2026 How we review solutions
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Environment Differences
Why Copy File Not Found Behaves Differently in Docker vs Local Development
Copy File Not Found frequently appears only in Docker environments because containers are isolated from the host system — they cannot use the host's DNS, filesystem mounts, or network interfaces without explicit configuration.
The most common Docker-only cause: services communicate by container name (e.g., postgres) on a user-defined network, but the container attempting the connection is on a different network or the default bridge network. On user-defined networks, Docker provides DNS resolution between containers. On the default bridge network (bridge0), it does not. Run docker network ls and docker inspect <container> | grep -i network to verify both containers share a network. A second Docker-specific cause: /etc/hosts entries on the host are not visible inside containers — if you rely on local hostname overrides for development, add them via --add-host in docker run or the extra_hosts key in Compose.Optional follow-up
Some users ask whether saving fixes for recurring errors would be useful when the same issue appears again.
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Frequently Asked Questions
What is build context?
The directory you specify with docker build - usually current dir.
How do I include parent files?
Move Dockerfile up or restructure to include needed files.
Related Resources
Also Known As
- Docker container error
- Docker build failure
- Container runtime error
- Docker daemon error
Common Search Variations
- "docker container won't start"
- "docker build error fix"
- "docker image not found"
- "container exited with error"
- "docker daemon not responding"
- "fix docker network error"
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