diff --git a/GUI/Model/Session/SimulationOptionsItem.cpp b/GUI/Model/Session/SimulationOptionsItem.cpp
index ba2bb9f55fb6bb40572b25dea237d4b477927cf0..3f512e7038595e4519909b4498252159b52e3a73 100644
--- a/GUI/Model/Session/SimulationOptionsItem.cpp
+++ b/GUI/Model/Session/SimulationOptionsItem.cpp
@@ -74,12 +74,12 @@ SimulationOptionsItem::SimulationOptionsItem() : SessionItem(M_TYPE)
         });
 }
 
-int SimulationOptionsItem::numberOfThreads() const
+unsigned SimulationOptionsItem::numberOfThreads() const
 {
-    return getItemValue(P_NTHREADS).toInt();
+    return getItemValue(P_NTHREADS).toUInt();
 }
 
-void SimulationOptionsItem::setNumberOfThreads(int number)
+void SimulationOptionsItem::setNumberOfThreads(unsigned number)
 {
     setItemValue(P_NTHREADS, number);
 }
diff --git a/GUI/Model/Session/SimulationOptionsItem.h b/GUI/Model/Session/SimulationOptionsItem.h
index 983351aca8e33a24a265cde7c5754f472afa90f8..acb5dbc6210151922a811abe4a251f9173fbc9a7 100644
--- a/GUI/Model/Session/SimulationOptionsItem.h
+++ b/GUI/Model/Session/SimulationOptionsItem.h
@@ -36,8 +36,8 @@ public:
 
     explicit SimulationOptionsItem();
 
-    void setNumberOfThreads(int n);
-    int numberOfThreads() const;
+    void setNumberOfThreads(unsigned n);
+    unsigned numberOfThreads() const;
 
     void setRunImmediately(bool runImmediately);
     bool runImmediately() const;