diff --git a/src/Mod/Part/App/FeaturePartFuse.cpp b/src/Mod/Part/App/FeaturePartFuse.cpp
index bd276a5f98..389f2849b7 100644
--- a/src/Mod/Part/App/FeaturePartFuse.cpp
+++ b/src/Mod/Part/App/FeaturePartFuse.cpp
@@ -136,24 +136,30 @@ App::DocumentObjectExecReturn *MultiFuse::execute(void)
 #else
             BRepAlgoAPI_Fuse mkFuse;
             TopTools_ListOfShape shapeArguments,shapeTools;
-            shapeArguments.Append(s.front());
+            const TopoDS_Shape& shape = s.front();
+            if (shape.IsNull())
+                throw Base::RuntimeError("Input shape is null");
+            shapeArguments.Append(shape);
+
             for (std::vector<TopoDS_Shape>::iterator it = s.begin()+1; it != s.end(); ++it) {
                 if (it->IsNull())
-                    throw Base::Exception("Input shape is null");
+                    throw Base::RuntimeError("Input shape is null");
                 shapeTools.Append(*it);
             }
+
             mkFuse.SetArguments(shapeArguments);
             mkFuse.SetTools(shapeTools);
             mkFuse.Build();
             if (!mkFuse.IsDone())
-                throw Base::Exception("MultiFusion failed");
+                throw Base::RuntimeError("MultiFusion failed");
+
             TopoDS_Shape resShape = mkFuse.Shape();
             for (std::vector<TopoDS_Shape>::iterator it = s.begin(); it != s.end(); ++it) {
                 history.push_back(buildHistory(mkFuse, TopAbs_FACE, resShape, *it));
             }
 #endif
             if (resShape.IsNull())
-                throw Base::Exception("Resulting shape is null");
+                throw Base::RuntimeError("Resulting shape is null");
 
             Base::Reference<ParameterGrp> hGrp = App::GetApplication().GetUserParameter()
                 .GetGroup("BaseApp")->GetGroup("Preferences")->GetGroup("Mod/Part/Boolean");