diff --git a/cloud_optimized_dicom/cod_object.py b/cloud_optimized_dicom/cod_object.py
index 9cac88f..3e29504 100644
--- a/cloud_optimized_dicom/cod_object.py
+++ b/cloud_optimized_dicom/cod_object.py
@@ -128,6 +128,8 @@ def __init__(
                 raise ErrorLogExistsError(
                     f"Cannot initialize; error log exists: {self.error_log_uri}"
                 )
+        # Initialize _metadata before locker, since acquire() calls get_metadata()
+        self._metadata = None
         # Only acquire lock for write/append mode WITH sync_on_exit=True
         # sync_on_exit=False means no lock (efficient for testing)
         self._locker = None
diff --git a/pyproject.toml b/pyproject.toml
index 0bbbfda..2edb18f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "cloud-optimized-dicom"
-version = "0.2.3"
+version = "0.2.4"
 description = "A library for efficiently storing and interacting with DICOM files in the cloud"
 readme = "README.md"
 authors = [