diff --git a/src/applications/search/field/PhabricatorSearchCheckboxesField.php b/src/applications/search/field/PhabricatorSearchCheckboxesField.php
--- a/src/applications/search/field/PhabricatorSearchCheckboxesField.php
+++ b/src/applications/search/field/PhabricatorSearchCheckboxesField.php
@@ -14,6 +14,14 @@
     return $this->options;
   }
 
+  public function getValue() {
+    $value = parent::getValue();
+    if (!$value) {
+      return array();
+    }
+    return $value;
+  }
+
   protected function getDefaultValue() {
     return array();
   }