diff --git a/unpack-trees.c b/unpack-trees.c
index 360844bda3..888cff81f9 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -1772,6 +1772,7 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
 
 	o->result.fsmonitor_last_update =
 		xstrdup_or_null(o->src_index->fsmonitor_last_update);
+	o->result.fsmonitor_has_run_once = o->src_index->fsmonitor_has_run_once;
 
 	/*
 	 * Sparse checkout loop #1: set NEW_SKIP_WORKTREE on existing entries