diff --git a/src/views/app.html b/src/views/app.html
index d5a8cd3ab..f40ba1f14 100644
--- a/src/views/app.html
+++ b/src/views/app.html
@@ -22,6 +22,10 @@
         </h5>
       </div>
       <div class="modal-body">
+        <p ng-show="postInstallConfirm.customAuth && !app.manifest.addons.email"></p>
+        <p ng-show="app.manifest.addons.email">This app is set up to allow all users with a mailbox on this Cloudron. Login with the email and Cloudron password to access the mailbox.</p>
+        <p ng-show="!postInstallConfirm.customAuth && !app.manifest.addons.email"> This app is set up to authenticate with the Cloudron User Directory. Cloudron users can login and use {{ appPostInstallConfirm.app.manifest.title }}.</p>
+
         <div ng-bind-html="app.manifest.postInstallMessage | markdown2html"></div>
         <div ng-show="app.manifest.documentationUrl">
           Please see the <a target="_blank" ng-href="{{ app.manifest.documentationUrl }}">documentation</a> for more information.
@@ -281,6 +285,10 @@
         <h4>First Time Setup</h4>
       </div>
       <div class="modal-body">
+        <p ng-show="postInstallMessage.customAuth && !app.manifest.addons.email"></p>
+        <p ng-show="app.manifest.addons.email">This app is set up to allow all users with a mailbox on this Cloudron. Login with the email and Cloudron password to access the mailbox.</p>
+        <p ng-show="!postInstallMessage.customAuth && !app.manifest.addons.email"> This app is set up to authenticate with the Cloudron User Directory. Cloudron users can login and use {{ appPostInstallConfirm.app.manifest.title }}.</p>
+
         <div ng-bind-html="app.manifest.postInstallMessage | markdown2html"></div>
       </div>
       <div class="modal-footer">
diff --git a/src/views/app.js b/src/views/app.js
index 913f552d4..1efaa2cde 100644
--- a/src/views/app.js
+++ b/src/views/app.js
@@ -142,10 +142,12 @@ angular.module('Application').controller('AppController', ['$scope', '$location'
     $scope.postInstallMessage = {
         confirmed: false,
         openApp: false,
+        customAuth: false,
 
         show: function (openApp) {
             $scope.postInstallMessage.confirmed = false;
             $scope.postInstallMessage.openApp = !!openApp;
+            $scope.postInstallMessage.customAuth = !($scope.app.manifest.addons['ldap'] || $scope.manifest.addons['oauth']);
 
             if (!$scope.app.manifest.postInstallMessage) return;
             $('#postInstallModal').modal('show');
@@ -1404,10 +1406,12 @@ angular.module('Application').controller('AppController', ['$scope', '$location'
     $scope.postInstallConfirm = {
         message: '',
         confirmed: false,
+        customAuth: false,
 
         show: function () {
             $scope.postInstallConfirm.message = $scope.app.manifest.postInstallMessage;
             $scope.postInstallConfirm.confirmed = false;
+            $scope.postInstallConfirm.customAuth = !($scope.app.manifest.addons['ldap'] || $scope.app.manifest.addons['oauth']);
 
             $('#postInstallConfirmModal').modal('show');