diff --git a/application/Espo/Core/Utils/Authentication/LDAP.php b/application/Espo/Core/Utils/Authentication/LDAP.php
index 5d7b146aa0..9e9ab4e1d0 100644
--- a/application/Espo/Core/Utils/Authentication/LDAP.php
+++ b/application/Espo/Core/Utils/Authentication/LDAP.php
@@ -99,6 +99,22 @@ class LDAP extends Espo
         return $this->utils;
     }
 
+    protected function getContainer()
+    {
+        return $this->getInjection('container');
+    }
+
+    protected function useSystemUser()
+    {
+        $systemUser = $this->getEntityManager()->getEntity('User', 'system');
+        if (!$systemUser) {
+            throw new Error("System user is not found.");
+        }
+
+        $this->getContainer()->setUser($systemUser);
+        $this->getEntityManager()->setUser($systemUser);
+    }
+
     protected function getLdapClient()
     {
         if (!isset($this->ldapClient)) {
@@ -183,7 +199,12 @@ class LDAP extends Espo
             ]
         ]);
 
-        if (!isset($user) && $this->getUtils()->getOption('createEspoUser')) {
+        if (!isset($user)) {
+            if (!$this->getUtils()->getOption('createEspoUser')) {
+                $this->useSystemUser();
+                throw new Error($this->getContainer()->get('language')->translate('ldapUserInEspoNotFound', 'messages', 'User'));
+            }
+
             $userData = $ldapClient->getEntry($userDn);
             $user = $this->createUser($userData, $isPortal);
         }
@@ -283,18 +304,11 @@ class LDAP extends Espo
             $data[$fieldName] = $fieldValue;
         }
 
-        $entityManager = $this->getEntityManager();
+        $this->useSystemUser();
 
-        $systemUser = $entityManager->getEntity('User', 'system');
-        if (!$systemUser) {
-            throw new Error("System user is not found");
-        }
-        $this->getInjection('container')->setUser($systemUser);
-        $entityManager->setUser($systemUser);
-
-        $user = $entityManager->getEntity('User');
+        $user = $this->getEntityManager()->getEntity('User');
         $user->set($data);
-        $entityManager->saveEntity($user);
+        $this->getEntityManager()->saveEntity($user);
 
         return $this->getEntityManager()->getEntity('User', $user->id);
     }
diff --git a/application/Espo/Core/Utils/Database/Schema/Converter.php b/application/Espo/Core/Utils/Database/Schema/Converter.php
index c1010dbef4..f0d9522da2 100644
--- a/application/Espo/Core/Utils/Database/Schema/Converter.php
+++ b/application/Espo/Core/Utils/Database/Schema/Converter.php
@@ -282,6 +282,9 @@ class Converter
     protected function prepareManyMany($entityName, $relationParams, $tables)
     {
         $tableName = Util::toUnderScore($relationParams['relationName']);
+        $GLOBALS['log']->debug('DBAL: prepareManyMany invoked for ' . $entityName, [
+            'tableName' => $tableName, 'parameters' => $relationParams
+        ]);
 
         if ($this->getSchema()->hasTable($tableName)) {
             $GLOBALS['log']->debug('DBAL: Table ['.$tableName.'] exists.');
@@ -297,17 +300,22 @@ class Converter
 
         //add midKeys to a schema
         $uniqueIndex = array();
-        foreach($relationParams['midKeys'] as $index => $midKey) {
-
-            $columnName = Util::toUnderScore($midKey);
-            $table->addColumn($columnName, $this->idParams['dbType'], $this->getDbFieldParams(array(
-                'type' => 'foreignId',
-                'len' => $this->idParams['len'],
-            )));
-            $table->addIndex(array($columnName), SchemaUtils::generateIndexName($columnName));
-
-            $uniqueIndex[] = $columnName;
-        }
+        if (empty($relationParams['midKeys'])) {
+            $GLOBALS['log']->debug('REBUILD: midKeys are empty!', [
+                'scope' => $entityName, 'tableName' => $tableName,
+                'parameters' => $relationParams
+            ]);
+        } else {
+            foreach($relationParams['midKeys'] as $index => $midKey) {
+                $columnName = Util::toUnderScore($midKey);
+                $table->addColumn($columnName, $this->idParams['dbType'], $this->getDbFieldParams(array(
+                    'type' => 'foreignId',
+                    'len' => $this->idParams['len'],
+                )));
+                $table->addIndex(array($columnName), SchemaUtils::generateIndexName($columnName));
+                $uniqueIndex[] = $columnName;
+            }
+        }        
         //END: add midKeys to a schema
 
         //add additionalColumns
diff --git a/application/Espo/Resources/i18n/en_US/User.json b/application/Espo/Resources/i18n/en_US/User.json
index 4f85f0d9c1..56ee8dec10 100644
--- a/application/Espo/Resources/i18n/en_US/User.json
+++ b/application/Espo/Resources/i18n/en_US/User.json
@@ -109,7 +109,8 @@
         "enterTotpCode": "Enter a code from your authenticator app.",
         "verifyTotpCode": "Scan the QR-code with your mobile authenticator app. If you have a trouble with scanning, you can enter the secret manually. After that you will see a 6-digit code in your application. Enter this code in the field below.",
         "generateAndSendNewPassword": "A new password will be generated and sent to the user's email address.",
-        "security2FaResetConfimation": "Are you sure you want to reset the current 2FA settings?"
+        "security2FaResetConfimation": "Are you sure you want to reset the current 2FA settings?",
+        "ldapUserInEspoNotFound": "User is not found in EspoCRM. Contact your administrator to create the user."
     },
     "options": {
         "gender": {