diff --git a/src/core/agent/agent_uid_generator.h b/src/core/agent/agent_uid_generator.h
index 626931c22..c3d46ab1d 100644
--- a/src/core/agent/agent_uid_generator.h
+++ b/src/core/agent/agent_uid_generator.h
@@ -52,7 +52,8 @@ class AgentUidGenerator {
         }
         if (search_index_ < map_->size()) {
           auto* scheduler = Simulation::GetActive()->GetScheduler();
-          return AgentUid(search_index_++, scheduler->GetSimulatedSteps());
+          return AgentUid(search_index_++, static_cast<AgentUid::Reused_t>(
+                                               scheduler->GetSimulatedSteps()));
         }
         // didn't find any empty slots -> disable defragmentation mode
         DisableDefragmentation();
@@ -74,7 +75,7 @@ class AgentUidGenerator {
 
   void DisableDefragmentation() {
     if (map_ != nullptr) {
-      counter_ = map_->size();
+      counter_ = static_cast<AgentUid::Index_t>(map_->size());
     }
     map_ = nullptr;
   }
diff --git a/src/core/environment/uniform_grid_environment.h b/src/core/environment/uniform_grid_environment.h
index a66e5cfa3..142cbe527 100644
--- a/src/core/environment/uniform_grid_environment.h
+++ b/src/core/environment/uniform_grid_environment.h
@@ -540,7 +540,7 @@ class UniformGridEnvironment : public Environment {
         std::sort(mutex_indices_.begin(), mutex_indices_.end());
       }
 
-      virtual ~GridNeighborMutex() = default;
+      ~GridNeighborMutex() override = default;
 
       void lock() override {  // NOLINT
         for (auto idx : mutex_indices_) {
@@ -576,7 +576,7 @@ class UniformGridEnvironment : public Environment {
       std::atomic_flag mutex_ = ATOMIC_FLAG_INIT;
     };
 
-    virtual ~GridNeighborMutexBuilder() = default;
+    ~GridNeighborMutexBuilder() override = default;
 
     void Update() {
       auto* grid = static_cast<UniformGridEnvironment*>(
diff --git a/src/core/resource_manager.h b/src/core/resource_manager.h
index 0e34ce705..ff7a0dc71 100644
--- a/src/core/resource_manager.h
+++ b/src/core/resource_manager.h
@@ -91,8 +91,8 @@ class ResourceManager {
     uid_ah_map_.clear();
     auto* agent_uid_generator = Simulation::GetActive()->GetAgentUidGenerator();
     uid_ah_map_.resize(agent_uid_generator->GetHighestIndex() + 1);
-    for (unsigned n = 0; n < agents_.size(); ++n) {
-      for (unsigned i = 0; i < agents_[n].size(); ++i) {
+    for (AgentHandle::NumaNode_t n = 0; n < agents_.size(); ++n) {
+      for (AgentHandle::ElementIdx_t i = 0; i < agents_[n].size(); ++i) {
         auto* agent = agents_[n][i];
         this->uid_ah_map_.Insert(agent->GetUid(), AgentHandle(n, i));
       }
@@ -217,9 +217,9 @@ class ResourceManager {
   virtual void ForEachAgent(
       const std::function<void(Agent*, AgentHandle)>& function,
       Functor<bool, Agent*>* filter = nullptr) {
-    for (uint64_t n = 0; n < agents_.size(); ++n) {
+    for (AgentHandle::NumaNode_t n = 0; n < agents_.size(); ++n) {
       auto& numa_agents = agents_[n];
-      for (uint64_t i = 0; i < numa_agents.size(); ++i) {
+      for (AgentHandle::ElementIdx_t i = 0; i < numa_agents.size(); ++i) {
         auto* a = numa_agents[i];
         if (!filter || (filter && (*filter)(a))) {
           function(a, AgentHandle(n, i));
@@ -325,8 +325,9 @@ class ResourceManager {
       uid_ah_map_.resize(uid.GetIndex() + 1);
     }
     agents_[numa_node].push_back(agent);
-    uid_ah_map_.Insert(uid,
-                       AgentHandle(numa_node, agents_[numa_node].size() - 1));
+    uid_ah_map_.Insert(
+        uid, AgentHandle(numa_node, static_cast<AgentHandle::ElementIdx_t>(
+                                        agents_[numa_node].size() - 1u)));
     if (type_index_) {
       type_index_->Add(agent);
     }
@@ -368,7 +369,9 @@ class ResourceManager {
     uint64_t i = 0;
     for (auto* agent : new_agents) {
       auto uid = agent->GetUid();
-      uid_ah_map_.Insert(uid, AgentHandle(numa_node, offset + i));
+      uid_ah_map_.Insert(
+          uid, AgentHandle(numa_node,
+                           static_cast<AgentHandle::ElementIdx_t>(offset + i)));
       agents_[numa_node][offset + i] = agent;
       i++;
     }
diff --git a/src/core/simulation_backup.cc b/src/core/simulation_backup.cc
index 52f68f889..4d167993a 100644
--- a/src/core/simulation_backup.cc
+++ b/src/core/simulation_backup.cc
@@ -44,7 +44,12 @@ size_t SimulationBackup::GetSimulationStepsFromBackup() {
     IntegralTypeWrapper<size_t>* wrapper = nullptr;
     bdm::GetPersistentObject(restore_file.c_str(), kSimulationStepName.c_str(),
                              wrapper);
-    return wrapper->Get();
+    if (wrapper != nullptr) {
+      return wrapper->Get();
+    } else {
+      Log::Fatal("SimulationBackup", "Failed to retrieve SimulationSteps.");
+      return 0;
+    }
   } else {
     Log::Fatal("SimulationBackup",
                "Requested to restore data, but no restore file given.");
diff --git a/src/core/util/thread_info.h b/src/core/util/thread_info.h
index b16541178..c87bca663 100644
--- a/src/core/util/thread_info.h
+++ b/src/core/util/thread_info.h
@@ -77,7 +77,7 @@ class ThreadInfo {
   /// metadata.
   void Renew() {
     max_threads_ = omp_get_max_threads();
-    numa_nodes_ = numa_num_configured_nodes();
+    numa_nodes_ = static_cast<uint16_t>(numa_num_configured_nodes());
 
     thread_numa_mapping_.clear();
     numa_thread_id_.clear();
@@ -97,8 +97,8 @@ class ThreadInfo {
     // (numa -> number of associated threads), and
     // (omp_thread_id -> thread id in numa)
     for (uint16_t n = 0; n < numa_nodes_; n++) {
-      uint64_t cnt = 0;
-      for (uint64_t t = 0; t < max_threads_; t++) {
+      int cnt = 0;
+      for (int t = 0; t < max_threads_; t++) {
         int numa = thread_numa_mapping_[t];
         if (n == numa) {
           numa_thread_id_[t] = cnt;
@@ -135,7 +135,7 @@ class ThreadInfo {
   static std::atomic<uint64_t> thread_counter_;
 
   /// Maximum number of threads for this simulation.
-  uint64_t max_threads_;
+  int max_threads_;
   /// Number of NUMA nodes on this machine.
   uint16_t numa_nodes_;
 
diff --git a/src/core/visualization/paraview/mapped_data_array.h b/src/core/visualization/paraview/mapped_data_array.h
index 56384844a..9a6a3cb99 100644
--- a/src/core/visualization/paraview/mapped_data_array.h
+++ b/src/core/visualization/paraview/mapped_data_array.h
@@ -117,6 +117,8 @@ struct GetDataMemberForVis {
 
 // -----------------------------------------------------------------------------
 struct MappedDataArrayInterface {
+  MappedDataArrayInterface() = default;
+  virtual ~MappedDataArrayInterface() = default;
   virtual void Update(const std::vector<Agent*>* agents, uint64_t start,
                       uint64_t end) = 0;
 };
@@ -435,12 +437,12 @@ void MappedDataArray<TScalar, TClass, TDataMember>::GetTuple(vtkIdType tuple_id,
       }
     }
     case Param::MappedDataArrayMode::kZeroCopy: {
-      auto* data = get_dm_((*agents_)[start_ + tuple_id]);
+      auto* temporary_data = get_dm_((*agents_)[start_ + tuple_id]);
       for (uint64_t i = 0; i < static_cast<uint64_t>(this->NumberOfComponents);
            ++i) {
-        tuple[i] = static_cast<double>(data[i]);
+        tuple[i] = static_cast<double>(temporary_data[i]);
         if (mode_ == Param::MappedDataArrayMode::kCache) {
-          data_[idx + i] = data[i];
+          data_[idx + i] = temporary_data[i];
           is_matching_[idx + i] = match_value_;
         }
       }
diff --git a/src/core/visualization/root/adaptor.h b/src/core/visualization/root/adaptor.h
index 9de55662b..19552e26a 100644
--- a/src/core/visualization/root/adaptor.h
+++ b/src/core/visualization/root/adaptor.h
@@ -79,7 +79,7 @@ class RootAdaptor {
       canvas_->GetListOfPrimitives()->Add(gGeoManager->GetTopVolume(),
                                           opt.c_str());
     }
-    canvas_->SetCanvasSize(w, h);
+    canvas_->SetCanvasSize(static_cast<UInt_t>(w), static_cast<UInt_t>(h));
     canvas_->Update();
     canvas_->Draw();
   }