diff --git a/hgext/mq.py b/hgext/mq.py
--- a/hgext/mq.py
+++ b/hgext/mq.py
@@ -492,7 +492,8 @@
                     n, name = entry
                     yield statusentry(bin(n), name)
                 elif l.strip():
-                    self.ui.warn(_('malformated mq status line: %s\n') % entry)
+                    self.ui.warn(_('malformated mq status line: %s\n') %
+                                 stringutil.pprint(entry))
                 # else we ignore empty lines
         try:
             lines = self.opener.read(self.statuspath).splitlines()