diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index 667170f..286827a 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -1964,7 +1964,9 @@
 const char* XMLDocument::ErrorName() const
 {
 	TIXMLASSERT( _errorID >= 0 && _errorID < XML_ERROR_COUNT );
-	return _errorNames[_errorID];
+    const char* errorName = _errorNames[_errorID];
+    TIXMLASSERT( errorName && errorName[0] );
+    return errorName;
 }
 
 void XMLDocument::PrintError() const