diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index 6a3cc985c4..c0e2bd6a06 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -146,6 +146,8 @@ void partial_clone_get_default_filter_spec(
 	/*
 	 * Parse default value, but silently ignore it if it is invalid.
 	 */
+	if (!core_partial_clone_filter_default)
+		return;
 	gently_parse_list_objects_filter(filter_options,
 					 core_partial_clone_filter_default,
 					 NULL);
diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh
index cc18b75c03..4984ca583d 100755
--- a/t/t0410-partial-clone.sh
+++ b/t/t0410-partial-clone.sh
@@ -23,7 +23,15 @@ promise_and_delete () {
 	delete_object repo "$HASH"
 }
 
+test_expect_success 'extensions.partialclone without filter' '
+	test_create_repo server &&
+	git clone --filter="blob:none" "file://$(pwd)/server" client &&
+	git -C client config --unset core.partialclonefilter &&
+	git -C client fetch origin
+'
+
 test_expect_success 'missing reflog object, but promised by a commit, passes fsck' '
+	rm -rf repo &&
 	test_create_repo repo &&
 	test_commit -C repo my_commit &&