diff --git a/src/pynwb/file.py b/src/pynwb/file.py
index 8f7be9fb6..e44d688a2 100644
--- a/src/pynwb/file.py
+++ b/src/pynwb/file.py
@@ -305,10 +305,12 @@ def __init__(self, **kwargs):
             raise ValueError("'timestamps_reference_time' must be a timezone-aware datetime object.")
 
         self.fields['file_create_date'] = getargs('file_create_date', kwargs)
+
         if self.fields['file_create_date'] is None:
-            self.fields['file_create_date'] = datetime.now(tzlocal())
-        if isinstance(self.fields['file_create_date'], datetime):
+            self.fields['file_create_date'] = [datetime.now(tzlocal())]
+        elif isinstance(self.fields['file_create_date'], datetime):
             self.fields['file_create_date'] = [self.fields['file_create_date']]
+
         self.fields['file_create_date'] = list(map(_add_missing_timezone, self.fields['file_create_date']))
 
         fieldnames = [