Maestro Fails to Detect Chrome Browser

Oct 13, 2025 by wbrum.org 101 views

Introduction

Maestro is a popular tool for automating mobile app testing, allowing developers to run tests on real devices and simulate various scenarios. However, some users have reported issues with Maestro failing to detect the Chrome browser in the GitHub Actions CI/CD environment, even when the browser is correctly launched and accessible locally. In this article, we will explore this issue and provide a step-by-step guide to reproduce and resolve it.

Is There an Existing Issue for This?

Before we dive into the issue, it's essential to check if there's an existing issue that has already been reported and resolved. After conducting a thorough search, we couldn't find any existing issues that match our problem description.

Steps to Reproduce

To reproduce this issue, follow these steps:

Step 1: Set Up Maestro on a macOS Self-Hosted GitHub Actions Runner

First, ensure that you have a self-hosted GitHub Actions runner set up on your macOS machine. This runner will be used to run the Maestro tests.

Step 2: Ensure Google Chrome is Installed on the Runner and Can Be Manually Launched from the Terminal

Next, verify that Google Chrome is installed on the runner and can be launched manually from the terminal. You can do this by running the following command:

open -a Google\ Chrome --remote-debugging-port=9223

This command will launch Chrome with the remote debugging port enabled.

Step 3: Use the Following GitHub Actions YAML Configuration

Create a new GitHub Actions YAML file with the following configuration:

name: Maestro Test

on:
  push:
    branches:
      - main

jobs:
  maestro-test:
    runs-on: macos-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v2
      - name: Run Maestro test command
        run: |
          maestro test tests/main.yaml -e URL=${{ env.DEPLOY_URL }}

This configuration will run the Maestro test command using the tests/main.yaml file and the DEPLOY_URL environment variable.

Step 4: Observe the Issue

After running the GitHub Actions workflow, observe the issue: Maestro reports "Want to use 0 devices, which is not enough to run 1 shards", despite Chrome being correctly launched and accessible locally.

Actual Results

The actual results of this issue are:

Maestro Fails to Detect Chrome Browser: Despite Chrome being correctly launched and accessible locally, Maestro fails to detect the browser in the GitHub Actions environment.
Error Message: The error message returned by Maestro is:

Want to use 0 devices, which is not enough to run 1 shards. Missing 1 device(s).
Not enough devices connected (1) to run the requested number of shards (1).

Issue Does Not Occur Locally: The issue does not occur when running the same test locally on the same machine, where Chrome is correctly detected, and the tests pass.

Expected Results

The expected results of this issue are:

Test Execution Proceeds Normally: The test execution should proceed normally, and Maestro should detect the Chrome browser correctly.

About App

The app in question is a web app, and it's not an open-source project.

About Environment

The environment in which this issue occurs is a GitHub Actions CI/CD environment using a self-hosted macOS runner on macOS 15.3.1.

Logs

The logs for this issue are:

Want to use 0 devices, which is not enough to run 1 shards. Missing 1 device(s).
Not enough devices connected (1) to run the requested number of shards (1)

Maestro Version

The version of Maestro being used is 1.39.13.

How Did You Install Maestro?

Maestro was installed using the install script provided by Maestro (https://get.maestro.mobile.dev).

Anything Else?

No additional information is available.

Conclusion

In conclusion, Maestro fails to detect the Chrome browser in the GitHub Actions CI/CD environment despite being correctly launched locally. This issue is reproducible by following the steps outlined in this article. The expected results of this issue are that the test execution should proceed normally, and Maestro should detect the Chrome browser correctly. However, the actual results are that Maestro fails to detect the browser, and the test execution fails. This issue is likely due to a configuration issue or a bug in Maestro. Further investigation is required to resolve this issue.

Troubleshooting Steps

To troubleshoot this issue, follow these steps:

Verify Maestro Configuration: Verify that the Maestro configuration is correct and that the Chrome browser is correctly launched and accessible locally.
Check GitHub Actions Configuration: Check the GitHub Actions configuration to ensure that it is correct and that the Maestro test command is being executed correctly.
Check Maestro Logs: Check the Maestro logs to see if there are any errors or warnings that may indicate the cause of the issue.
Update Maestro Version: Update the Maestro version to the latest version to see if the issue is resolved.
Contact Maestro Support: Contact Maestro support for further assistance and guidance.

Q: What is the issue with Maestro detecting Chrome browser in GitHub Actions CI/CD environment?

A: Maestro fails to detect the Chrome browser in the GitHub Actions CI/CD environment despite being correctly launched locally. This issue is reproducible by following the steps outlined in our previous article.

Q: What are the symptoms of this issue?

A: The symptoms of this issue are:

Maestro Fails to Detect Chrome Browser: Despite Chrome being correctly launched and accessible locally, Maestro fails to detect the browser in the GitHub Actions environment.
Error Message: The error message returned by Maestro is:

Want to use 0 devices, which is not enough to run 1 shards. Missing 1 device(s).
Not enough devices connected (1) to run the requested number of shards (1).

Issue Does Not Occur Locally: The issue does not occur when running the same test locally on the same machine, where Chrome is correctly detected, and the tests pass.

Q: What are the expected results of this issue?

A: The expected results of this issue are:

Test Execution Proceeds Normally: The test execution should proceed normally, and Maestro should detect the Chrome browser correctly.

Q: What are the possible causes of this issue?

A: The possible causes of this issue are:

Configuration Issue: A configuration issue in the Maestro or GitHub Actions configuration may be causing the issue.
Bug in Maestro: A bug in Maestro may be causing the issue.
Incompatible Maestro Version: An incompatible version of Maestro may be causing the issue.

Q: How can I troubleshoot this issue?

A: To troubleshoot this issue, follow these steps:

Verify Maestro Configuration: Verify that the Maestro configuration is correct and that the Chrome browser is correctly launched and accessible locally.
Check GitHub Actions Configuration: Check the GitHub Actions configuration to ensure that it is correct and that the Maestro test command is being executed correctly.
Check Maestro Logs: Check the Maestro logs to see if there are any errors or warnings that may indicate the cause of the issue.
Update Maestro Version: Update the Maestro version to the latest version to see if the issue is resolved.
Contact Maestro Support: Contact Maestro support for further assistance and guidance.

Q: How can I resolve this issue?

A: To resolve this issue, follow the troubleshooting steps outlined above. If the issue persists, contact Maestro support for further assistance and guidance.

Q: Is this issue specific to GitHub Actions or can it occur in other environments?

A: This issue can occur in other environments, not just GitHub Actions. However, the symptoms and causes of the issue may vary depending on the environment.

Q: Can I prevent this issue from occurring in the future?

A: Yes, you can prevent this issue from occurring in the future by:

Verifying Maestro Configuration: Verify that the Maestro configuration is correct and that the Chrome browser is correctly launched and accessible locally.
Checking GitHub Actions Configuration: Check the GitHub Actions configuration to ensure that it is correct and that the Maestro test command is being executed correctly.
Updating Maestro Version: Update the Maestro version to the latest version to ensure that you have the latest features and bug fixes.

By following these Q&A, you should be able to better understand the issue and how to troubleshoot and resolve it.