KB: Failed to Add Class Member Error During the ECO
Created: 十月 29, 2025 | Updated: 十月 29, 2025
Altium Designer
Users may encounter the error message “Failed to add class members” during the Engineering Change Order (ECO) process. This typically occurs when a component designator already exists on the PCB or when component classes were previously generated without placing footprints. In some cases, the error is linked to comparator settings that ignore component class differences, especially in multi-channel designs. The issue can often be resolved by adjusting comparator settings, deleting existing components, or proceeding with the ECO despite the warning.
Solution Details
Failed to Add Class Member Error During ECO
When the Error Occurs
During the ECO import process, users may receive the error message "Failed to add class members". This can happen in various scenarios, such as when updating component classes or synchronizing schematic and PCB data.
Why This Happens
The error typically occurs due to one of the following reasons:
- A component designator already exists or is placed on the PCB, causing a conflict during class member addition.
- Component classes were generated earlier, but footprints were not placed. On a subsequent ECO, the system attempts to re-add the class members, triggering the warning.
- The comparator setting for component class differences is set to Ignore differences, preventing the generation of multichannel component classes and causing errors for design channel classes.
What to Do
To resolve the issue, try one or more of the following solutions:
- Solution 1: Proceed with the ECO despite the warning. In many cases, the warning resolves itself after execution.
- Solution 2: Delete the existing component from the PCB and re-import via ECO.
- Solution 3: Update comparator settings to detect component class differences.
How to Do It
Solution 1: Proceed with ECO
- Run the ECO process as usual.
- Ignore the “Failed to add class members” warning.
- Complete the ECO and verify that the class members are correctly added. It is recommended to use the Execute command during the ECO instead of Validate. Any unwanted changes can be undone through the Undo command.
Solution 2: Delete and Re-import
- Open the PCB document.
- Locate and delete the existing component causing the conflict.
- Run the ECO import again to re-add the component and its class membership.
Solution 3: Update Comparator Settings
- Go to Project » Project Options.
- Navigate to the Comparator tab.
- Ensure the Extra Component Classes option is set to Find differences.
- Apply changes and re-run the ECO process.
Additional Notes
- This error is more common in multi-channel designs where component classes are reused or updated frequently.
- Always verify comparator settings before running ECO to avoid class membership conflicts.