Input or output missing root element error

When a mapping uses an input or output root document element that can no longer be found in the input or output schema, it results in input or output missing root element error.

This error happens if you modify a schema or when you import a mapping with inconsistent metadata. In the case of inconsistent metadata, check the mapping.input/output.element from the file and verify that the values are correct. You can manually modify the values and try to open the mapping again.