diff --git a/jina/optimizers/__init__.py b/jina/optimizers/__init__.py
index 3acfd9251eadd..bd3a6e5072c4b 100644
--- a/jina/optimizers/__init__.py
+++ b/jina/optimizers/__init__.py
@@ -115,7 +115,7 @@ def __init__(
             parameter_yaml: str,
             evaluation_callback: 'OptimizerCallback',
             n_trials: int,
-            workspace_base_dir: str = '',
+            workspace_base_dir: str = '.',
             sampler: str = 'TPESampler',
             direction: str = 'maximize',
             seed: int = 42,