diff --git a/src/externalldap.js b/src/externalldap.js
index 7dc26e94c..bdef98a59 100644
--- a/src/externalldap.js
+++ b/src/externalldap.js
@@ -151,7 +151,7 @@ function sync(progressCallback, callback) {
                 scope: 'sub'    // We may have to make this configurable
             };
 
-            debug(`Listing users at ${externalLdapConfig.baseDn} with filter ${externalLdapConfig.filter}`);
+            debug(`Listing users at ${externalLdapConfig.baseDn} with filter ${externalLdapConfig.filter} and usernameField=${externalLdapConfig.usernameField}`);
 
             client.search(externalLdapConfig.baseDn, opts, function (error, result) {
                 if (error) return callback(new BoxError(BoxError.EXTERNAL_ERROR, error));