diff --git a/src/util/src/ttime.c b/src/util/src/ttime.c
index 176f9be7fbc5c7c3d1a2252d1bcfc83eb1a1b2cd..96e0eaa214fcb78269c26945ef04171c21aa66f7 100644
--- a/src/util/src/ttime.c
+++ b/src/util/src/ttime.c
@@ -56,11 +56,13 @@ int64_t user_mktime64(const unsigned int year0, const unsigned int mon0,
     year -= 1;
   }
 
-  int64_t res = 367*((int64_t)mon)/12;
-
-  res += ((int64_t)(year/4 - year/100 + year/400 + day + year*365) - 719499);  // this value may be less than 0
+  //int64_t res = (((((int64_t) (year/4 - year/100 + year/400 + 367*mon/12 + day) +
+  //               year*365 - 719499)*24 + hour)*60 + min)*60 + sec);
+  int64_t res;
+  res  = 367*((int64_t)mon)/12;
+  res += year/4 - year/100 + year/400 + day + year*365 - 719499;
   res  = res*24;
-  res  = ((res + hour) * 60 + min) * 60 + sec;  
+  res  = ((res + hour) * 60 + min) * 60 + sec;
 
   return (res + timezone);
 }