diff --git a/XMLCONF b/XMLCONF
index 25f7f6f..73fc3bb 100644
--- a/XMLCONF
+++ b/XMLCONF
@@ -1799,11 +1799,7 @@ eduni/namespaces/1.0/011.xml [not validating:] not-wf [validating:] not-wf
 eduni/namespaces/1.0/012.xml [not validating:] not-wf [validating:] not-wf
 eduni/namespaces/1.0/013.xml [not validating:] not-wf [validating:] invalid
 eduni/namespaces/1.0/014.xml [not validating:] not-wf [validating:] invalid
-eduni/namespaces/1.0/015.xml [not validating:] FAILED:
-  well-formedness violation not detected
-[
-Bad QName syntax: colon at start
-]
+eduni/namespaces/1.0/015.xml [not validating:] not-wf [validating:] invalid
 eduni/namespaces/1.0/016.xml [not validating:] not-wf [validating:] invalid
 eduni/namespaces/1.0/017.xml [not validating:] input [validating:] invalid
 eduni/namespaces/1.0/018.xml [not validating:] input [validating:] invalid
@@ -1851,4 +1847,4 @@ eduni/namespaces/1.0/046.xml [not validating:] input [validating:] FAILED:
 [
 Colon in ID attribute name
 ]
-5/1829 tests failed; 333 tests were skipped
\ No newline at end of file
+4/1829 tests failed; 333 tests were skipped
\ No newline at end of file
diff --git a/xml/xml-parse.lisp b/xml/xml-parse.lisp
index 9435848..3484ada 100644
--- a/xml/xml-parse.lisp
+++ b/xml/xml-parse.lisp
@@ -3326,6 +3326,8 @@
     (if pos
 	(let ((prefix (subseq qname 0 pos))
 	      (local-name (subseq qname (1+ pos))))
+	  (when (zerop pos)
+	    (wf-error nil "empty namespace prefix"))
 	  (if (nc-name-p local-name)
 	      (values prefix local-name)
 	      (wf-error nil "~S is not a valid NcName."