diff --git a/src/loadFlash.cpp b/src/loadFlash.cpp
index 3f42c4f..f732cb8 100644
--- a/src/loadFlash.cpp
+++ b/src/loadFlash.cpp
@@ -43,7 +43,7 @@ SimuData *CosmoTool::loadFlashMulti(const char *fname, int id, int loadflags)
     data->time    = time;
 
     h5_read_runtime_parameters(&file, &lbox, &npart);
-    data->NumPart = npart;
+    data->TotalNumPart = data->NumPart = npart;
     data->BoxSize = lbox/kpc2cm;
 
     // particle data