diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 883cebb173..e7cd24d7a3 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -4917,6 +4917,7 @@ void GLCanvas3D::_render_thumbnail_internal(ThumbnailData& thumbnail_data, const
     const Transform3d& projection_matrix = camera.get_projection_matrix();
 
     const ModelObjectPtrs &model_objects    = GUI::wxGetApp().model().objects;
+    const int              extruders_count  = wxGetApp().extruders_edited_cnt();
     std::vector<ColorRGBA> extruders_colors = get_extruders_colors();
     for (GLVolume *vol : visible_volumes) {
         vol->model.set_color((vol->printable && !vol->is_outside) ? vol->color : ColorRGBA::GRAY());
@@ -4930,7 +4931,7 @@ void GLCanvas3D::_render_thumbnail_internal(ThumbnailData& thumbnail_data, const
         shader->set_uniform("view_normal_matrix", view_normal_matrix);
 
         const ModelVolume    &model_volume = *model_objects[vol->object_idx()]->volumes[vol->volume_idx()];
-        const size_t          extruder_idx = get_extruder_color_idx(model_volume);
+        const size_t          extruder_idx = get_extruder_color_idx(model_volume, extruders_count);
         TriangleSelectorMmGui ts(model_volume.mesh(), extruders_colors, extruders_colors[extruder_idx]);
         ts.deserialize(model_volume.mmu_segmentation_facets.get_data(), true);
         ts.request_update_render_data();
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp b/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp
index 1e60c118b6..7f4d4c28d6 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp
@@ -529,7 +529,8 @@ void GLGizmoMmuSegmentation::update_model_object() const
 
 void GLGizmoMmuSegmentation::init_model_triangle_selectors()
 {
-    const ModelObject *mo = m_c->selection_info()->model_object();
+    const int          extruders_count = wxGetApp().extruders_edited_cnt();
+    const ModelObject *mo              = m_c->selection_info()->model_object();
     m_triangle_selectors.clear();
 
     // Don't continue when extruders colors are not initialized
@@ -543,7 +544,7 @@ void GLGizmoMmuSegmentation::init_model_triangle_selectors()
         // This mesh does not account for the possible Z up SLA offset.
         const TriangleMesh *mesh = &mv->mesh();
 
-        size_t extruder_idx = get_extruder_color_idx(*mv);
+        size_t extruder_idx = get_extruder_color_idx(*mv, extruders_count);
         m_triangle_selectors.emplace_back(std::make_unique<TriangleSelectorMmGui>(*mesh, m_modified_extruders_colors, m_original_extruders_colors[extruder_idx]));
         // Reset of TriangleSelector is done inside TriangleSelectorMmGUI's constructor, so we don't need it to perform it again in deserialize().
         m_triangle_selectors.back()->deserialize(mv->mmu_segmentation_facets.get_data(), false);
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.hpp b/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.hpp
index 1bc01ba1bb..23e8318c37 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.hpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.hpp
@@ -156,9 +156,12 @@ private:
 
 std::vector<ColorRGBA> get_extruders_colors();
 
-inline size_t get_extruder_color_idx(const ModelVolume &model_volume)
+inline size_t get_extruder_color_idx(const ModelVolume &model_volume, const int extruders_count)
 {
-    return (model_volume.extruder_id() > 0) ? model_volume.extruder_id() - 1 : 0;
+    if (const int extruder_id = model_volume.extruder_id(); extruder_id <= 0 || extruder_id > extruders_count)
+        return 0;
+    else
+        return extruder_id - 1;
 }
 
 } // namespace Slic3r