diff --git a/gtk/gtksettings.c b/gtk/gtksettings.c
index 0288c61716..12d2aa1af6 100644
--- a/gtk/gtksettings.c
+++ b/gtk/gtksettings.c
@@ -2717,7 +2717,7 @@ settings_update_provider (GdkScreen       *screen,
                           GtkCssProvider **old,
                           GtkCssProvider  *new)
 {
-  if (*old != new)
+  if (screen != NULL && *old != new)
     {
       if (*old)
         {