A user is attempting to Copy a feature or Convert an artifact and is receiving an error similar to the following;
Unable to convert Defects to User Stories
This error is caused by the fact that the customer had hidden the field in selected projects and subsequently changed the values in the feature configuration. Thus the feature they are trying to copy has a hidden field with a now invalid value in it. This is essentially working as designed in that the user would have been warned when changing or editing the values of the list filed with the following message. "Values will be changed only for projects that are showing this field".
The field will need to be made visible and the value changed to a legitimate choice in the feature or artifact to be copied. Once the value is changed the feature or artifact can be successfully copied. The field can then be hidden again.