diff --git a/app/core/gimpimage-colormap.c b/app/core/gimpimage-colormap.c
index 7843a1235d..e50b1129f5 100644
--- a/app/core/gimpimage-colormap.c
+++ b/app/core/gimpimage-colormap.c
@@ -144,7 +144,7 @@ gimp_image_colormap_update_formats (GimpImage *image)
 
   g_free (format_name);
 
-  if (private->palette)
+  if (private->palette && gimp_palette_get_n_colors (private->palette) > 0)
     {
       guchar *colormap;
       gint    n_colors;