diff --git a/c_tools/mock/loaders/multidark_loader.cpp b/c_tools/mock/loaders/multidark_loader.cpp
index fbe26ba..e3f90de 100644
--- a/c_tools/mock/loaders/multidark_loader.cpp
+++ b/c_tools/mock/loaders/multidark_loader.cpp
@@ -82,7 +82,7 @@ public:
       simu->Pos[k] = new float[allocated];
       simu->Vel[k] = new float[allocated];
     }
-    simu->Id = new long[allocated];
+    simu->Id = new int64_t[allocated];
     long *uniqueID = new long[allocated];
     long *index = new long[allocated];
 
diff --git a/c_tools/mock/loaders/sdf_loader.cpp b/c_tools/mock/loaders/sdf_loader.cpp
index dd8a8d9..8c47b49 100644
--- a/c_tools/mock/loaders/sdf_loader.cpp
+++ b/c_tools/mock/loaders/sdf_loader.cpp
@@ -203,7 +203,7 @@ public:
       }
     if (load_flags & NEED_GADGET_ID)
       {
-        d->Id = new long[numPartToLoad];
+        d->Id = new int64_t[numPartToLoad];
         SETUP_READ("ident", d->Id);
       }
 #undef SETUP_READ