You are currently viewing How to Resolve Docker Exec Format Error

How to Resolve Docker Exec Format Error

In the vast area of technology, Docker has emerged as a revolutionary tool for software development and deployment. Docker containers allow developers to package applications and their dependencies into a standardized unit for seamless deployment across various environments. However, like any technology, Docker has its challenges. One common issue that developers often encounter is the “Docker Exec Format Error.”

One easy way to avoid Docker exec format error and all other errors is opting for our Docker Consulting services. Our Docker experts make all these errors stay away from you.

In this blog post, we’ll understand this error in simple terms, explaining what it is, why it happens, and how you can troubleshoot and fix it.

What is Docker Exec Format Error?

When you’re working with Docker, you might encounter an error message that looks something like this: “exec format error.” This error occurs when you try to run a Docker container, but the executable file format inside the container is not compatible with the host system.

Why Does Docker Exec Format Error Happen?

Docker containers are designed to run on different operating systems and architectures. However, if the container image you’re trying to run was built for a different operating system or CPU architecture than your host system, you’ll encounter the exec format error. For instance, if you’re trying to run a container built for Linux on a Windows system, or if the container image is compiled for a different CPU architecture, Docker won’t be able to execute it, leading to this error.

We encounter the following Docker error message upon launching the Docker container.

How to resolve Docker exec format Error

When our customers face this problem, our Support Engineers look at the entrypoint in the Docker file.

A Docker file is like a recipe book. It contains all the steps needed to make a Docker picture using commands similar to what you type on your computer. We use it to build the Docker image.

The error happens because a special line called a shebang was missing in the Docker entrypoint script. To fix it, we add this shebang line into the script.

Also Check: Our blog post on docker overlay2 cleanup

How to fix Docker Exec Format Error

To solve the Docker exec format error, we add something called a shebang to the beginning of the script. This shebang is a special line in the script that tells the computer how to run it.

The shebang looks like this: #!/bin/bash. It needs to be the first line of the script because the computer checks the first part of the file. So we put this shebang at the start of the script to fix the problem.

Another way to fix the error is by running a specific command in Docker. We use the following command:

How to resolve Docker exec format Error

The output will look like this:

How to resolve Docker exec format Error

Doing this helps to resolve the Docker error.

Check Out: Our blog post on docker ps

Troubleshooting Docker Exec Format Error

Now that we understand why this error occurs, let’s explore some troubleshooting steps to resolve it:

  • Check the Docker Image: First and foremost, ensure that the Docker image you’re using is compatible with your host system. Check the documentation or repository where you obtained the image to confirm its compatibility.
  • Verify CPU Architecture: If you’re facing this error on a system with a different CPU architecture, you might need an image specifically built for that architecture. You can check your system’s architecture using terminal commands like uname -m on Linux or systeminfo | find “System Type” on Windows.
  • Update Dockerfile: If you’re creating your own Docker images, make sure your Dockerfile specifies the correct base image compatible with your host system. For example, if you’re on a Linux system, use a Linux-based base image.
  • Use Multi-Platform Images: Docker supports multi-platform images, allowing you to build images that can run on different architectures. When pulling images, you can use the –platform flag to specify the desired platform, ensuring compatibility.
  • Consider Emulation: In some cases, you can use emulation tools like QEMU to run containers built for different architectures. However, this method might be slower and less efficient.


While encountering a Docker exec format error might seem scary, understanding its root cause and following the appropriate troubleshooting steps can help you resolve the issue. Always ensure that you’re using compatible images and that your Dockerfile is correctly configured for your host system. With these considerations in mind, you can navigate the world of Docker containers more smoothly, ensuring your applications run seamlessly across various environments. 

Still need help with Docker? Contact our support team. Our support engineers will help you in resolving this error. Get started here.