diff --git a/util/sconfig/main.c b/util/sconfig/main.c
index a7b2ce6..1fd4404 100644
--- a/util/sconfig/main.c
+++ b/util/sconfig/main.c
@@ -872,7 +872,7 @@
 	for (cur = *head; cur != NULL; prev = cur, cur = cur->next) {
 		const int sort = strcmp(r->key, cur->key);
 		if (sort == 0) {
-			printf("ERROR: duplicate 'register' key.\n");
+			printf("ERROR: duplicate 'register' key '%s'.\n", r->key);
 			exit(1);
 		}
 		if (sort < 0)