diff --git a/c_tools/mock/generateMock.cpp b/c_tools/mock/generateMock.cpp
index 0b77e5c..40fe59e 100644
--- a/c_tools/mock/generateMock.cpp
+++ b/c_tools/mock/generateMock.cpp
@@ -592,6 +592,9 @@ int main(int argc, char **argv)
   else
     makeBoxFromSimulation(loader, simuOut, metricOperation, args_info);
 
+  // Reset the random number generator
+  gsl_rng_set(rng, args_info.subsample_seed_arg);
+
   long loaded = 0;
   for (int nf = 0; nf < loader->num_files(); nf++)
     {
diff --git a/c_tools/mock/loaders/gadget_loader.cpp b/c_tools/mock/loaders/gadget_loader.cpp
index a76416a..a06d09f 100644
--- a/c_tools/mock/loaders/gadget_loader.cpp
+++ b/c_tools/mock/loaders/gadget_loader.cpp
@@ -97,6 +97,7 @@ public:
     filteredCopy(d->Id, accepted, d->NumPart);
     filteredCopy(d->type, accepted, d->NumPart);
     delete[] accepted;
+    d->NumPart = numAccepted;
 
     return d;
   }