## Introduction to Xiaomi Home Assistant
The Xiaomi Home Assistant is a cutting-edge smart home system designed to integrate and control various Xiaomi devices, including the lumi.gateway.mieu01. This gateway is a crucial component in the Xiaomi smart home ecosystem, enabling features such as motion detection, volume control, and light adjustment. However, users may encounter issues with certain features, such as the motion detection on/off functionality not working as expected.

## Understanding the Motion Detection Issue
The error message 'Failed to perform action switch/turn_off. Execution error, Property not writable, switch.lumi_de_275936540_mieu01_guard_mode_p_2_1, Gateway Guard Mode' indicates a problem with toggling the motion detection feature. This issue might arise from incompatibilities between the Xiaomi Home integration and the HACS (Home Assistant Community Store) or problems with the device itself.

## Steps to Reproduce the Issue
To troubleshoot the motion detection issue, start by verifying that all other features, such as volume control and light adjustment, are functioning correctly. If these features work as expected, the problem might be specific to the motion detection feature or its integration with the Xiaomi Home Assistant.

## Expected Behavior
The expected behavior of the motion detection feature is to turn on or off without throwing any errors. If the feature is not working as expected, it may be due to a configuration issue or a problem with the integration.

## Troubleshooting
1. **Check Device Compatibility**: Ensure that the lumi.gateway.mieu01 is compatible with the Xiaomi Home integration and the version of Home Assistant being used.
2. **Update Integration**: Make sure the Xiaomi Home integration is updated to the latest version, as newer versions may resolve known issues.
3. **Consult Logs**: Review the Home Assistant logs for any error messages related to the motion detection feature. These logs can provide valuable insights into what might be causing the issue.
4. **Reset Device**: If possible, reset the lumi.gateway.mieu01 to its factory settings and then reintegrate it with the Xiaomi Home Assistant.
5. **Community Support**: Reach out to the Home Assistant community or Xiaomi support forums for further assistance, as others may have encountered and resolved similar issues.

## Conclusion
Troubleshooting issues with the Xiaomi Home Assistant, such as the motion detection feature not working, involves a systematic approach to identifying and resolving the problem. By checking device compatibility, updating the integration, consulting logs, resetting the device, and seeking community support, users can often resolve these issues and enjoy the full functionality of their Xiaomi smart home devices.