diff --git a/PQAnalysis/cli/gen2xyz.py b/PQAnalysis/cli/gen2xyz.py
index 216b4d1e..8f86d360 100644
--- a/PQAnalysis/cli/gen2xyz.py
+++ b/PQAnalysis/cli/gen2xyz.py
@@ -69,6 +69,7 @@ def add_arguments(cls, parser: _ArgumentParser) -> None:
         parser.add_argument(
             '--nobox',
             action='store_true',
+            default=False,
             help='Do not print the box.'
         )
 
diff --git a/PQAnalysis/cli/rst2xyz.py b/PQAnalysis/cli/rst2xyz.py
index 89599699..fc99aa65 100644
--- a/PQAnalysis/cli/rst2xyz.py
+++ b/PQAnalysis/cli/rst2xyz.py
@@ -69,6 +69,7 @@ def add_arguments(cls, parser: _ArgumentParser) -> None:
         parser.add_argument(
             '--nobox',
             action='store_true',
+            default=False,
             help='Do not print the box.'
         )
 
diff --git a/PQAnalysis/cli/traj2box.py b/PQAnalysis/cli/traj2box.py
index 93cd7311..2b2bc3ae 100644
--- a/PQAnalysis/cli/traj2box.py
+++ b/PQAnalysis/cli/traj2box.py
@@ -74,6 +74,7 @@ def add_arguments(cls, parser: _ArgumentParser) -> None:
         parser.add_argument(
             '--vmd',
             action='store_true',
+            default=False,
             help='Output in VMD format.'
         )