diff --git a/src/calibre/ebooks/html/input.py b/src/calibre/ebooks/html/input.py
index 73c2cf2c1e..6e172ef188 100644
--- a/src/calibre/ebooks/html/input.py
+++ b/src/calibre/ebooks/html/input.py
@@ -152,7 +152,7 @@ class HTMLFile(object):
         return hash(self.path)
 
     def __str__(self):
-        return 'HTMLFile:%d:%s:%s'%(self.level, 'b' if self.is_binary else 'a', self.path)
+        return 'HTMLFile:%d:%s:%r'%(self.level, 'b' if self.is_binary else 'a', self.path)
 
     def __repr__(self):
         return unicode_type(self)