diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8581aab..686dd14 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ Changelog
 
 - Support non-standard, text-based forensic reports sent by some mail hosts
 - Set forensic report version to `None` (`null` in JSON) if the report was in a non-standard format and/or is missing a version number
+- The default value of the `mailbox` `batch_size` option is now `10` (use `0` for no limit)
 
 8.1.1
 -----
diff --git a/README.rst b/README.rst
index 20fda9d..7067ea0 100644
--- a/README.rst
+++ b/README.rst
@@ -203,7 +203,7 @@ The full set of configuration options are:
     - ``watch`` - bool: Use the IMAP ``IDLE`` command to process messages as they arrive or poll MS Graph for new messages
     - ``delete`` - bool: Delete messages after processing them, instead of archiving them
     - ``test`` - bool: Do not move or delete messages
-    - ``batch_size`` - int: Number of messages to read and process before saving. Defaults to all messages if not set.
+    - ``batch_size`` - int: Number of messages to read and process before saving. Default 10. Use 0 for no limit.
 
 - ``imap``
     - ``host`` - str: The IMAP server hostname or IP address
diff --git a/docs/index.rst b/docs/index.rst
index 90f6e9b..be6995f 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -195,7 +195,7 @@ The full set of configuration options are:
     - ``watch`` - bool: Use the IMAP ``IDLE`` command to process messages as they arrive or poll MS Graph for new messages
     - ``delete`` - bool: Delete messages after processing them, instead of archiving them
     - ``test`` - bool: Do not move or delete messages
-    - ``batch_size`` - int: Number of messages to read and process before saving. Defaults to all messages if not set.
+    - ``batch_size`` - int: Number of messages to read and process before saving. Default 10. Use 0 for no limit.
 
 - ``imap``
     - ``host`` - str: The IMAP server hostname or IP address
diff --git a/parsedmarc/__init__.py b/parsedmarc/__init__.py
index 6976e0b..c03794b 100644
--- a/parsedmarc/__init__.py
+++ b/parsedmarc/__init__.py
@@ -1034,7 +1034,7 @@ def get_dmarc_reports_from_mailbox(connection: MailboxConnection,
                                    dns_timeout=6.0,
                                    strip_attachment_payloads=False,
                                    results=None,
-                                   batch_size=None,
+                                   batch_size=10,
                                    create_folders=True):
     """
     Fetches and parses DMARC reports from a mailbox
@@ -1053,6 +1053,7 @@ def get_dmarc_reports_from_mailbox(connection: MailboxConnection,
           forensic report results
         results (dict): Results from the previous run
         batch_size (int): Number of messages to read and process before saving
+            (use 0 for no limit)
         create_folders (bool): Whether to create the destination folders
           (not used in watch)
 
diff --git a/parsedmarc/cli.py b/parsedmarc/cli.py
index 5722f57..35fa4c1 100644
--- a/parsedmarc/cli.py
+++ b/parsedmarc/cli.py
@@ -393,8 +393,6 @@ def _main():
                 opts.mailbox_test = mailbox_config.getboolean("test")
             if "batch_size" in mailbox_config:
                 opts.mailbox_batch_size = mailbox_config.getint("batch_size")
-            else:
-                opts.mailbox_batch_size = None
 
         if "imap" in config.sections():
             imap_config = config["imap"]
@@ -467,8 +465,6 @@ def _main():
                                "configuration section has been deprecated. "
                                "Use this option in the mailbox configuration "
                                "section instead.")
-            else:
-                opts.mailbox_batch_size = None
 
         if "msgraph" in config.sections():
             graph_config = config["msgraph"]