diff --git a/format.c b/format.c
index 8202a256..55b40ec0 100644
--- a/format.c
+++ b/format.c
@@ -3327,7 +3327,7 @@ format_find(struct format_tree *ft, const char *key, int modifiers,
 	fte = format_table_get(key);
 	if (fte != NULL) {
 		value = fte->cb(ft);
-		if (fte->type == FORMAT_TABLE_TIME)
+		if (fte->type == FORMAT_TABLE_TIME && value != NULL)
 			t = ((struct timeval *)value)->tv_sec;
 		else
 			found = value;