diff --git a/plugins/ktcore/KTDocumentActions.php b/plugins/ktcore/KTDocumentActions.php
index 5fe720d..d254a3e 100644
--- a/plugins/ktcore/KTDocumentActions.php
+++ b/plugins/ktcore/KTDocumentActions.php
@@ -440,6 +440,7 @@ class KTDocumentCheckOutAction extends KTDocumentAction {
         $oForm->setValidators(array(
             array('ktcore.validators.string', array(
                 'test' => 'reason',
+                'min_length' => 1,
                 'max_length' => 250,
                 'output' => 'reason',
             )),