diff --git a/interface/web/mail/mail_user_edit.php b/interface/web/mail/mail_user_edit.php
index 0c9110bb73e410195a371ba0f1372579cf5bd683..8166b5814e6da77f5321343b4d6ea7a4fb2754b9 100644
--- a/interface/web/mail/mail_user_edit.php
+++ b/interface/web/mail/mail_user_edit.php
@@ -166,7 +166,7 @@ class page_action extends tform_actions {
 			}
 
 			// Check the quota and adjust
-			if(isset($_POST["quota"]) && $client["limit_mailquota"] >= 0 && $app->functions->intval($this->dataRecord["quota"]) * 1024 * 1024 != $this->oldDataRecord['quota']) {
+			if(isset($_POST["quota"]) && $client["limit_mailquota"] >= 0 && (($app->functions->intval($this->dataRecord["quota"]) * 1024 * 1024 != $this->oldDataRecord['quota']) || ($_POST["quota"] <= 0))) {
 				$tmp = $app->db->queryOneRecord("SELECT sum(quota) as mailquota FROM mail_user WHERE mailuser_id != ".$app->functions->intval($this->id)." AND ".$app->tform->getAuthSQL('u'));
 				$mailquota = $tmp["mailquota"] / 1024 / 1024;
 				$new_mailbox_quota = $app->functions->intval($this->dataRecord["quota"]);
@@ -179,6 +179,7 @@ class page_action extends tform_actions {
 				unset($tmp);
 				unset($tmp_quota);
 			}
+			
 		} // end if user is not admin