diff --git a/source/blender/blenloader/intern/versioning_400.cc b/source/blender/blenloader/intern/versioning_400.cc
index 0dfec2997ed..e387969fb5b 100644
--- a/source/blender/blenloader/intern/versioning_400.cc
+++ b/source/blender/blenloader/intern/versioning_400.cc
@@ -992,9 +992,17 @@ static void do_version_glare_node_options_to_inputs(const Scene *scene,
     return 1.0f - blender::math::clamp(-mix, 0.0f, 1.0f);
   };
 
-  /* Function to remap the Size property to its new range. See function description. */
+  /* Find the render size to guess the Size value. The node tree might not belong to a scene, so we
+   * just assume an arbitrary HDTV 1080p render size. */
   blender::int2 render_size;
-  BKE_render_resolution(&scene->r, true, &render_size.x, &render_size.y);
+  if (scene) {
+    BKE_render_resolution(&scene->r, true, &render_size.x, &render_size.y);
+  }
+  else {
+    render_size = blender::int2(1920, 1080);
+  }
+
+  /* Function to remap the Size property to its new range. See function description. */
   const int max_render_size = blender::math::reduce_max(render_size);
   auto size_to_linear = [&](const int size) {
     if (storage->type == CMP_NODE_GLARE_BLOOM) {