diff --git a/src/pretix/control/forms/__init__.py b/src/pretix/control/forms/__init__.py
index 180fbb0741..396944fb1f 100644
--- a/src/pretix/control/forms/__init__.py
+++ b/src/pretix/control/forms/__init__.py
@@ -98,7 +98,7 @@ class ClearableBasenameFileInput(forms.ClearableFileInput):
 class SizeFileField(forms.FileField):
 
     def __init__(self, *args, **kwargs):
-        self.max_size = kwargs.pop("max_size")
+        self.max_size = kwargs.pop("max_size", None)
         super().__init__(*args, **kwargs)
 
     @staticmethod