diff --git a/phpBB/includes/acp/acp_profile.php b/phpBB/includes/acp/acp_profile.php
index 1b0ec4b5d5..fc08c7e8e8 100644
--- a/phpBB/includes/acp/acp_profile.php
+++ b/phpBB/includes/acp/acp_profile.php
@@ -509,6 +509,14 @@ class acp_profile
 						// Get the number of options if this key is 'field_maxlen'
 						$var = request_var('field_default_value', 0);
 					}*/
+					else if ($field_type == FIELD_INT && $key == 'field_default_value')
+					{
+						// Permit an empty string
+						if (request_var('field_default_value', '') === '')
+						{
+							$var = '';
+						}
+					}
 
 					$cp->vars[$key] = $var;
 				}
diff --git a/phpBB/includes/functions_profile_fields.php b/phpBB/includes/functions_profile_fields.php
index 9e356414a9..db1925bdcc 100644
--- a/phpBB/includes/functions_profile_fields.php
+++ b/phpBB/includes/functions_profile_fields.php
@@ -624,7 +624,7 @@ class custom_profile
 			}
 			else
 			{
-				if (!$preview && isset($user->profile_fields[$user_ident]) && is_null($user->profile_fields[$user_ident]))
+				if (!$preview && array_key_exists($user_ident, $user->profile_fields) && is_null($user->profile_fields[$user_ident]))
 				{
 					$value = NULL;
 				}