diff --git a/libs/pbd/xml++.cc b/libs/pbd/xml++.cc
index 69187995a1..5fb777bdc7 100644
--- a/libs/pbd/xml++.cc
+++ b/libs/pbd/xml++.cc
@@ -155,6 +155,20 @@ XMLTree::write() const
 	xmlSetDocCompressMode(doc, _compression);
 	writenode(doc, _root, doc->children, 1);
 	result = xmlSaveFormatFileEnc(_filename.c_str(), doc, "UTF-8", 1);
+#ifndef NDEBUG
+	if (result == -1) {
+		xmlErrorPtr xerr = xmlGetLastError ();
+		if (!xerr) {
+			std::cerr << "unknown XML error during xmlSaveFormatFileEnc()." << std::endl;
+		} else {
+			std::cerr << "xmlSaveFormatFileEnc: error"
+				<< " domain: " << xerr->domain
+				<< " code: " << xerr->code
+				<< " msg: " << xerr->message
+				<< std::endl;
+		}
+	}
+#endif
 	xmlFreeDoc(doc);
 
 	if (result == -1) {