diff --git a/moses/TranslationModel/UG/mm/tpt_pickler.h b/moses/TranslationModel/UG/mm/tpt_pickler.h
index 5a42ced01..1e4cd39c1 100644
--- a/moses/TranslationModel/UG/mm/tpt_pickler.h
+++ b/moses/TranslationModel/UG/mm/tpt_pickler.h
@@ -44,7 +44,7 @@ namespace tpt
 
   char const *binread(char const* p, uint16_t& buf);
   char const *binread(char const* p, uint32_t& buf);
-  char const *binread(char const* p, filepos_type& buf);
+  char const *binread(char const* p, uint64_t& buf);
   char const *binread(char const* p, float& buf);
 #ifdef __clang__
   char const *binread(char const* p, size_t& buf);