diff --git a/src/addons.js b/src/addons.js
index 5d1538381..ef312b453 100644
--- a/src/addons.js
+++ b/src/addons.js
@@ -21,7 +21,7 @@ var appdb = require('./appdb.js'),
     async = require('async'),
     clients = require('./clients.js'),
     config = require('./config.js'),
-    DatabaseError = require('./databaseerror.js'),
+    ClientsError = clients.ClientsError,
     debug = require('debug')('box:addons'),
     docker = require('./docker.js'),
     dockerConnection = docker.connection,
@@ -287,7 +287,7 @@ function setupOauth(app, options, callback) {
     var scope = 'profile';
 
     clients.delByAppIdAndType(appId, clients.TYPE_OAUTH, function (error) { // remove existing creds
-        if (error && error.reason !== DatabaseError.NOT_FOUND) return callback(error);
+        if (error && error.reason !== ClientsError.NOT_FOUND) return callback(error);
 
         clients.add(appId, clients.TYPE_OAUTH, redirectURI, scope, function (error, result) {
             if (error) return callback(error);
@@ -313,7 +313,7 @@ function teardownOauth(app, options, callback) {
     debugApp(app, 'teardownOauth');
 
     clients.delByAppIdAndType(app.id, clients.TYPE_OAUTH, function (error) {
-        if (error && error.reason !== DatabaseError.NOT_FOUND) console.error(error);
+        if (error && error.reason !== ClientsError.NOT_FOUND) console.error(error);
 
         appdb.unsetAddonConfig(app.id, 'oauth', callback);
     });
@@ -328,7 +328,7 @@ function setupSimpleAuth(app, options, callback) {
     var scope = 'profile';
 
     clients.delByAppIdAndType(app.id, clients.TYPE_SIMPLE_AUTH, function (error) { // remove existing creds
-        if (error && error.reason !== DatabaseError.NOT_FOUND) return callback(error);
+        if (error && error.reason !== ClientsError.NOT_FOUND) return callback(error);
 
         clients.add(appId, clients.TYPE_SIMPLE_AUTH, '', scope, function (error, result) {
             if (error) return callback(error);
@@ -356,7 +356,7 @@ function teardownSimpleAuth(app, options, callback) {
     debugApp(app, 'teardownSimpleAuth');
 
     clients.delByAppIdAndType(app.id, clients.TYPE_SIMPLE_AUTH, function (error) {
-        if (error && error.reason !== DatabaseError.NOT_FOUND) console.error(error);
+        if (error && error.reason !== ClientsError.NOT_FOUND) console.error(error);
 
         appdb.unsetAddonConfig(app.id, 'simpleauth', callback);
     });
diff --git a/src/apptask.js b/src/apptask.js
index 27f241d9d..fb6f26c82 100644
--- a/src/apptask.js
+++ b/src/apptask.js
@@ -38,8 +38,8 @@ var addons = require('./addons.js'),
     certificates = require('./certificates.js'),
     clients = require('./clients.js'),
     config = require('./config.js'),
+    ClientsError = clients.ClientsError,
     database = require('./database.js'),
-    DatabaseError = require('./databaseerror.js'),
     debug = require('debug')('box:apptask'),
     docker = require('./docker.js'),
     ejs = require('ejs'),
@@ -172,7 +172,7 @@ function removeOAuthProxyCredentials(app, callback) {
     assert.strictEqual(typeof callback, 'function');
 
     clients.delByAppIdAndType(app.id, clients.TYPE_PROXY, function (error) {
-        if (error && error.reason !== DatabaseError.NOT_FOUND) {
+        if (error && error.reason !== ClientsError.NOT_FOUND) {
             debugApp(app, 'Error removing OAuth client id', error);
             return callback(error);
         }
diff --git a/src/auth.js b/src/auth.js
index ac41edd5b..d253b0564 100644
--- a/src/auth.js
+++ b/src/auth.js
@@ -12,11 +12,11 @@ var assert = require('assert'),
     BearerStrategy = require('passport-http-bearer').Strategy,
     clients = require('./clients'),
     ClientPasswordStrategy = require('passport-oauth2-client-password').Strategy,
+    ClientsError = clients.ClientsError,
     DatabaseError = require('./databaseerror'),
     debug = require('debug')('box:auth'),
     LocalStrategy = require('passport-local').Strategy,
     crypto = require('crypto'),
-    groups = require('./groups'),
     passport = require('passport'),
     tokendb = require('./tokendb'),
     user = require('./user'),
@@ -67,7 +67,7 @@ function initialize(callback) {
             // username is actually client id here
             // password is client secret
             clients.get(username, function (error, client) {
-                if (error && error.reason === DatabaseError.NOT_FOUND) return callback(null, false);
+                if (error && error.reason === ClientsError.NOT_FOUND) return callback(null, false);
                 if (error) return callback(error);
                 if (client.clientSecret != password) return callback(null, false);
                 return callback(null, client);
@@ -85,7 +85,7 @@ function initialize(callback) {
 
     passport.use(new ClientPasswordStrategy(function (clientId, clientSecret, callback) {
         clients.get(clientId, function(error, client) {
-            if (error && error.reason === DatabaseError.NOT_FOUND) return callback(null, false);
+            if (error && error.reason === ClientsError.NOT_FOUND) return callback(null, false);
             if (error) { return callback(error); }
             if (client.clientSecret != clientSecret) { return callback(null, false); }
             return callback(null, client);
diff --git a/src/routes/oauth2.js b/src/routes/oauth2.js
index 1aecefe3f..1b66c0452 100644
--- a/src/routes/oauth2.js
+++ b/src/routes/oauth2.js
@@ -5,8 +5,8 @@ var appdb = require('../appdb'),
     assert = require('assert'),
     authcodedb = require('../authcodedb'),
     clients = require('../clients'),
+    ClientsError = clients.ClientsError,
     config = require('../config.js'),
-    constants = require('../constants.js'),
     DatabaseError = require('../databaseerror'),
     debug = require('debug')('box:routes/oauth2'),
     eventlog = require('../eventlog.js'),
@@ -405,7 +405,7 @@ var authorization = [
         debug('authorization: client %s with callback to %s.', clientId, redirectURI);
 
         clients.get(clientId, function (error, client) {
-            if (error && error.reason === DatabaseError.NOT_FOUND) return callback(null, false);
+            if (error && error.reason === ClientsError.NOT_FOUND) return callback(null, false);
             if (error) return callback(error);
 
             // ignore the origin passed into form the client, but use the one from the clientdb
diff --git a/src/simpleauth.js b/src/simpleauth.js
index a1b92c7f6..f6ecb964d 100644
--- a/src/simpleauth.js
+++ b/src/simpleauth.js
@@ -86,7 +86,7 @@ function login(req, res, next) {
     if (typeof req.body.password !== 'string') return next(new HttpError(400, 'password is required'));
 
     loginLogic(req.body.clientId, req.body.username, req.body.password, function (error, result) {
-        if (error && error.reason === DatabaseError.NOT_FOUND) return next(new HttpError(401, 'Unknown client'));
+        if (error && error.reason === ClientsError.NOT_FOUND) return next(new HttpError(401, 'Unknown client'));
         if (error && error.reason === ClientsError.INVALID_CLIENT) return next(new HttpError(401, 'Unkown client'));
         if (error && error.reason === UserError.NOT_FOUND) return next(new HttpError(401, 'Forbidden'));
         if (error && error.reason === AppsError.NOT_FOUND) return next(new HttpError(401, 'Unkown app'));