diff --git a/app/Http/Controllers/AccountApiController.php b/app/Http/Controllers/AccountApiController.php
index f93bf85461bb..bee5c09c7094 100644
--- a/app/Http/Controllers/AccountApiController.php
+++ b/app/Http/Controllers/AccountApiController.php
@@ -39,7 +39,7 @@ class AccountApiController extends BaseAPIController
 
     public function register(RegisterRequest $request)
     {
-        if (! \App\Models\LookupUser::validateEmail($request->email)) {
+        if (! \App\Models\LookupUser::validateField('email', $request->email)) {
             return $this->errorResponse(['message' => trans('texts.email_taken')], 500);
         }
 
diff --git a/app/Http/Controllers/AccountController.php b/app/Http/Controllers/AccountController.php
index ea4538dd84e4..62d9d8ff62be 100644
--- a/app/Http/Controllers/AccountController.php
+++ b/app/Http/Controllers/AccountController.php
@@ -1102,7 +1102,7 @@ class AccountController extends BaseController
         $user = Auth::user();
         $email = trim(strtolower(Input::get('email')));
 
-        if (! \App\Models\LookupUser::validateEmail($email, $user)) {
+        if (! \App\Models\LookupUser::validateField('email', $email, $user)) {
             return Redirect::to('settings/' . ACCOUNT_USER_DETAILS)
                 ->withError(trans('texts.email_taken'))
                 ->withInput();
@@ -1219,7 +1219,7 @@ class AccountController extends BaseController
         $email = trim(strtolower(Input::get('email')));
         $user = Auth::user();
 
-        if (! \App\Models\LookupUser::validateEmail($email, $user)) {
+        if (! \App\Models\LookupUser::validateField('email', $email, $user)) {
             return 'taken';
         }
 
@@ -1264,7 +1264,7 @@ class AccountController extends BaseController
         $email = trim(strtolower(Input::get('new_email')));
         $password = trim(Input::get('new_password'));
 
-        if (! \App\Models\LookupUser::validateEmail($email, $user)) {
+        if (! \App\Models\LookupUser::validateField('email', $email, $user)) {
             return '';
         }
 
diff --git a/app/Http/Controllers/UserController.php b/app/Http/Controllers/UserController.php
index 6cce8ec58fc1..dd7f96f23cf8 100644
--- a/app/Http/Controllers/UserController.php
+++ b/app/Http/Controllers/UserController.php
@@ -182,7 +182,7 @@ class UserController extends BaseController
                             ->withInput();
             }
 
-            if (! \App\Models\LookupUser::validateEmail(Input::get('email'), $user)) {
+            if (! \App\Models\LookupUser::validateField('email', Input::get('email'), $user)) {
                 return Redirect::to($userPublicId ? 'users/edit' : 'users/create')
                     ->withError(trans('texts.email_taken'))
                     ->withInput();
diff --git a/app/Models/LookupUser.php b/app/Models/LookupUser.php
index bf4b2e17e022..c1edd1231c17 100644
--- a/app/Models/LookupUser.php
+++ b/app/Models/LookupUser.php
@@ -47,7 +47,7 @@ class LookupUser extends LookupModel
         config(['database.default' => $current]);
     }
 
-    public static function validateEmail($email, $user = false)
+    public static function validateField($field, $value, $user = false)
     {
         if (! env('MULTI_DB_ENABLED')) {
             return true;
@@ -58,7 +58,7 @@ class LookupUser extends LookupModel
 
         config(['database.default' => DB_NINJA_LOOKUP]);
 
-        $lookupUser = LookupUser::whereEmail($email)->first();
+        $lookupUser = LookupUser::where($field, '=', $value)->first();
 
         if ($user) {
             $lookupAccount = LookupAccount::whereAccountKey($accountKey)->firstOrFail();
diff --git a/app/Ninja/Repositories/AccountRepository.php b/app/Ninja/Repositories/AccountRepository.php
index b7035a8fbe77..ebcf0cff5f70 100644
--- a/app/Ninja/Repositories/AccountRepository.php
+++ b/app/Ninja/Repositories/AccountRepository.php
@@ -16,6 +16,7 @@ use App\Models\InvoiceItem;
 use App\Models\Language;
 use App\Models\User;
 use App\Models\UserAccount;
+use App\Models\LookupUser;
 use Auth;
 use Input;
 use Request;
@@ -430,6 +431,10 @@ class AccountRepository
 
     public function updateUserFromOauth($user, $firstName, $lastName, $email, $providerId, $oauthUserId)
     {
+        if (! LookupUser::validateField('oauth_user_key', $providerId . '-' . $oauthUserId)) {
+            return trans('texts.oauth_taken');
+        }
+
         if (! $user->registered) {
             $rules = ['email' => 'email|required|unique:users,email,'.$user->id.',id'];
             $validator = Validator::make(['email' => $email], $rules);
@@ -439,7 +444,7 @@ class AccountRepository
                 return $messages->first('email');
             }
 
-            if (! \App\Models\LookupUser::validateEmail($email, $user)) {
+            if (! LookupUser::validateField('email', $email, $user)) {
                 return trans('texts.email_taken');
             }
 
diff --git a/resources/lang/en/texts.php b/resources/lang/en/texts.php
index 0e92e3cf5faf..4214fd57a5b5 100644
--- a/resources/lang/en/texts.php
+++ b/resources/lang/en/texts.php
@@ -2244,6 +2244,7 @@ $LANG = array(
     'white_label_license_error' => 'Failed to validate the license, check storage/logs/laravel-error.log for more details.',
     'plan_price' => 'Plan Price',
     'wrong_confirmation' => 'Incorrect confirmation code',
+    'oauth_taken' => 'The account is already registered',
 
 );