diff --git a/crates/lib/src/bootc_composefs/repo.rs b/crates/lib/src/bootc_composefs/repo.rs
index 6a8d707b3b..4fe7809567 100644
--- a/crates/lib/src/bootc_composefs/repo.rs
+++ b/crates/lib/src/bootc_composefs/repo.rs
@@ -813,6 +813,8 @@ mod tests {
             .path()
             .join(crate::store::COMPOSEFS)
             .join("objects/sentinel");
+        // composefs-rs creates objects/ lazily, so it may not exist yet.
+        std::fs::create_dir_all(object_path.parent().unwrap()).unwrap();
         std::fs::write(&object_path, b"retained").unwrap();
         drop(repo);