diff --git a/src/slic3r/GUI/GLModel.cpp b/src/slic3r/GUI/GLModel.cpp
index 3dd15c3fdd..92296030e1 100644
--- a/src/slic3r/GUI/GLModel.cpp
+++ b/src/slic3r/GUI/GLModel.cpp
@@ -456,8 +456,9 @@ void GLModel::init_from(const indexed_triangle_set& its)
     data.reserve_vertices(3 * its.indices.size());
     data.reserve_indices(3 * its.indices.size());
 
-    // Read user preference: smooth normals enabled
-    const bool smooth_normals_enabled = wxGetApp().app_config != nullptr && wxGetApp().app_config->get_bool(SETTING_OPENGL_PHONG_SMOOTH_NORMALS);
+    // CLI thumbnail generation can initialize models without a wx application.
+    const bool smooth_normals_enabled = wxApp::GetInstance() != nullptr && wxGetApp().app_config != nullptr &&
+                                        wxGetApp().app_config->get_bool(SETTING_OPENGL_PHONG_SMOOTH_NORMALS);
 
     if (smooth_normals_enabled) {
         // Use per-corner smooth normals (via IGL)