diff --git a/src/evolve_halos.cpp b/src/evolve_halos.cpp
index 5103095..53e2999 100644
--- a/src/evolve_halos.cpp
+++ b/src/evolve_halos.cpp
@@ -247,10 +247,10 @@ void track_total_baryons(Cosmology &cosmology, ExecutionParameters execparams, S
 				number_minor_mergers += galaxy.interaction.minor_mergers;
 				number_disk_instabil += galaxy.interaction.disk_instabilities;
 
+				galaxy.mean_stellar_age += (galaxy.sfr_disk + galaxy.sfr_bulge_mergers + galaxy.sfr_bulge_diskins) * deltat * mean_age;
+				galaxy.total_stellar_mass_ever_formed += (galaxy.sfr_disk + galaxy.sfr_bulge_mergers + galaxy.sfr_bulge_diskins) * deltat;
+
 				if(execparams.output_sf_histories){
-        
-					galaxy.mean_stellar_age += (galaxy.sfr_disk + galaxy.sfr_bulge_mergers + galaxy.sfr_bulge_diskins) * deltat * mean_age;
-					galaxy.total_stellar_mass_ever_formed += (galaxy.sfr_disk + galaxy.sfr_bulge_mergers + galaxy.sfr_bulge_diskins) * deltat;
 
 					HistoryItem hist_galaxy;
 					hist_galaxy.sfr_disk            = galaxy.sfr_disk;
diff --git a/src/galaxy_writer.cpp b/src/galaxy_writer.cpp
index 2b679e5..c1f7f4b 100644
--- a/src/galaxy_writer.cpp
+++ b/src/galaxy_writer.cpp
@@ -374,7 +374,11 @@ void HDF5GalaxyWriter::write_galaxies(hdf5::Writer &file, int snapshot, const st
 				mstars_burst_diskinstabilities.push_back(galaxy.diskinstabilities_burst_stars.mass);
 				mstars_bulge_diskins_assembly.push_back(galaxy.diskinstabilities_assembly_stars.mass);
 				mstars_stripped.push_back(galaxy.stars_tidal_stripped.mass);
-				mean_stellar_age.push_back(galaxy.mean_stellar_age / galaxy.total_stellar_mass_ever_formed);
+				auto age = 0;
+				if(galaxy.total_stellar_mass_ever_formed > 0){
+					age = galaxy.mean_stellar_age / galaxy.total_stellar_mass_ever_formed;
+				}
+				mean_stellar_age.push_back(age);
 
 				// Gas components
 				mgas_disk.push_back(galaxy.disk_gas.mass);
diff --git a/src/tree_builder.cpp b/src/tree_builder.cpp
index 7494b46..f62e962 100644
--- a/src/tree_builder.cpp
+++ b/src/tree_builder.cpp
@@ -383,8 +383,6 @@ void TreeBuilder::define_accretion_rate_from_dm(const std::vector<MergerTreePtr>
 		for(int snapshot=sim_params.max_snapshot; snapshot >= sim_params.min_snapshot; snapshot--) {
 				for(auto &halo: tree->halos_at(snapshot)){
 
-					const auto &ascendants = halo->ascendants;
-
 					auto Mvir_asc = halo->total_mass_ascendants();
 
 					// Define accreted baryonic mass.