Unfortunately we cannot reproduce this issue locally. You can find working dhtmlxDataProcessor examples here dhtmlx.com/docs/products/dht … processor/
Working connector examples are available at your dhtmlxConnector package.
If issue still occurs please contact directly customer.support@dhtmlx.com
After any update operation with treegrid there is alert message arrives
Such problem can occurs if xml content was sent with incorrect content-type or there was some output before xml start
If you are using connectors - double check that there is no any extra output before its initialization ( any whitespace or newline is matter )