diff --git a/includes/activation_form.inc b/includes/activation_form.inc
index fda8f02..9fcbd04 100644
--- a/includes/activation_form.inc
+++ b/includes/activation_form.inc
@@ -103,9 +103,15 @@ function os2intra_user_import_activate_form_validate($form, &$form_state) {
         }
 
         // Check if it matches the users birthday field
-        $birthday_field = field_get_items('user', $user, 'field_os2intra_birthdate');
-        if ($input_birthday !== $birthday_field[0]['value']) {
-          form_set_error('form', 'Please check your input.');
+        $birthday_field_name = variable_get('os2intra_user_import_birthday_field');
+        if (!empty(field_info_instance('user', $birthday_field_name, 'user'))) {
+          $birthday_field = field_get_items('user', $user, $birthday_field_name);
+          if ($input_birthday !== date("dmy", strtotime($birthday_field[0]['value']))) {
+            form_set_error('form', 'Please check your input.');
+          }
+        }
+        else {
+          form_set_error('form', 'Activation form has wrong configuration settings. Please contact site administrator');
         }
       }
 
diff --git a/includes/csv_mapping.inc b/includes/csv_mapping.inc
index ffb1229..4202372 100644
--- a/includes/csv_mapping.inc
+++ b/includes/csv_mapping.inc
@@ -3,6 +3,13 @@
  * Helper function to parse file contents to array with relevant info
  */
 function _os2intra_user_import_process_file($file_path, $lines = FALSE) {
+  $identification_method = variable_get('os2intra_user_import_activate_identification', OS2INTRA_USER_IMPORT_ACTIVATE_IDENTIFICATION);
+  $rows = array();
+  if (empty($identification_method)) {
+    drupal_set_message('User activation mode is not setup. Please check user import configuration /admin/config/os2intra/user_import/settings', 'error');
+    return $rows;
+  }
+
   // CSV field mapping
   // rewrite for settings page?
   $mapping = variable_get('os2intra_mapping');
@@ -59,22 +66,15 @@ function _os2intra_user_import_process_file($file_path, $lines = FALSE) {
     }
     // Skip if row has no ad_id and no employee_id
     if ($mapped_row['ad_id'] == '' && $mapped_row['employee_id'] == '' ) {
+      os2intra_user_import_save_log('', 'No ad_id and no employee_id found in row: ' . implode(';', $row));
       continue;
     }
 
-    // Generate ad_id if missing
+    // Try to set ad_id from ad_name column.
     if (!isset($mapped_row['ad_id'])) {
       if (isset($mapped_row['ad_name']) && !empty($mapped_row['ad_name'])) {
         $mapped_row['ad_id'] = $mapped_row['ad_name'];
       }
-      else {
-        if (variable_get('os2intra_generate_username')) {
-          $mapped_row['ad_id'] = os2intra_user_import_generate_username($mapped_row);
-        }
-        else {
-          continue;
-        }
-      }
     }
 
     $rows[] = $mapped_row;
diff --git a/includes/settings_form.inc b/includes/settings_form.inc
index 710bb19..8c59d99 100644
--- a/includes/settings_form.inc
+++ b/includes/settings_form.inc
@@ -154,6 +154,7 @@ $csv_cols_fallback_1 = array(
     '#type' => 'fieldset',
     '#title' => t('User activation'),
     '#collapsible' => TRUE,
+    '#weight' => -100,
   );
 
   $form['os2intra_user_import_activate']['activation_fields'] = array(
@@ -164,7 +165,9 @@ $csv_cols_fallback_1 = array(
   $form['os2intra_user_import_activate']['activation_fields']['os2intra_user_import_activate_identification'] = array(
     '#title' => t('User identification'),
     '#type' => 'select',
+    '#required' => TRUE,
     '#options' => array(
+      '' => t('None'),
       'ad_id' => t('AD id'),
       'employee_id' => ('Employee number'),
     ),
@@ -358,12 +361,6 @@ $csv_cols_fallback_1 = array(
     '#description'   => t('If checked only membership from current import will be added'),
     '#default_value' => variable_get('os2intra_revoke_og_roles')
   );
-  // Variable which contains settings to determinate how username should be generated.
-  $form['os2intra_structure_settings']['os2intra_generate_username'] = array(
-    '#type'          => 'checkbox',
-    '#title'         => t('Generate unique user name from "user full name + department name" when AD id is not present'),
-    '#default_value' => variable_get('os2intra_generate_username')
-  );
   // Variable which contains birthday format.
   $form['os2intra_structure_settings']['os2intra_user_import_birthdate_db_format'] = array(
     '#type'          => 'textfield',
diff --git a/includes/users.inc b/includes/users.inc
index 272d993..f33ea31 100644
--- a/includes/users.inc
+++ b/includes/users.inc
@@ -49,23 +49,59 @@ function os2intra_user_import_disable_users() {
 }
 
 /**
- * Check if the user is already created in the system
+ * Check if the user is already created in the system.
  */
-function os2intra_user_import_check_users(&$users, $duplicate_emails, $duplicate_ids) {
+function os2intra_user_import_check_users(&$users) {
   $update_users = array();
+
+  // Check duplicated emails. Drupal users should have unique email.
+  $dup_emails = array();
+  $user_email = array_column($users, 'email');
+  if (!empty($user_email) && count($users) !== count(array_unique($user_email))) {
+    $dup_emails = array_unique(array_diff_assoc($user_email, array_unique($user_email)));
+    os2intra_user_import_save_log('', 'Duplicate email found in import file: ' . implode(', ', $dup_emails));
+  }
+
+  // Check duplicated AD id. AD id values should be unique.
+  $ad_id = array_column($users, 'ad_id');
+  $dup_id = array();
+  if (!empty($ad_id) && count($users) !== count(array_unique($ad_id))) {
+    $dup_id = array_unique(array_diff_assoc($ad_id, array_unique($ad_id)));
+    os2intra_user_import_save_log('', 'Duplicate User AD id found in import file: ' . implode(', ', $dup_id));
+  }
+
+  $identification_method = variable_get('os2intra_user_import_activate_identification', OS2INTRA_USER_IMPORT_ACTIVATE_IDENTIFICATION);
+  // For employee_id activation mode employee_id values should be unique.
+  if ($identification_method == 'employee_id') {
+    $employee_id = array_column($users, 'employee_id');
+    $dup_em_id = array();
+    if (!empty($employee_id) && count($users) !== count(array_unique($employee_id))) {
+      $dup_em_id = array_unique(array_diff_assoc($employee_id, array_unique($employee_id)));
+      os2intra_user_import_save_log('', 'Duplicate employee id found in import file: ' . implode(', ', $dup_em_id));
+    }
+  }
+
   foreach ($users as $key => $user) {
-    if (array_search($user['email'], $duplicate_emails) !== false) {
+    if (array_search($user['email'], $dup_emails) !== FALSE) {
       os2intra_user_import_save_log('', 'Duplicate email found: Skip user ' . $user['email']);
       unset($users[$key]);
       continue;
     }
 
-    if (array_search($user['ad_id'], $duplicate_ids) !== false) {
+    if (array_search($user['ad_id'], $dup_id) !== FALSE) {
       unset($users[$key]);
       os2intra_user_import_save_log('', 'Duplicate user AD found: Skip user ' . $user['ad_id']);
       continue;
     }
 
+    if ($identification_method == 'employee_id') {
+      if (array_search($user['employee_id'], $dup_em_id) !== FALSE) {
+        unset($users[$key]);
+        os2intra_user_import_save_log('', 'Duplicate user employee id found: Skip user ' . $user['employee_id']);
+        continue;
+      }
+    }
+
     $result = NULL;
 
     $identification_method = variable_get('os2intra_user_import_activate_identification', OS2INTRA_USER_IMPORT_ACTIVATE_IDENTIFICATION);
@@ -217,7 +253,7 @@ function os2intra_user_import_save_user($user, $uid = '') {
   // This is only done in order to migrate user groups, from users before the
   // import groups field was added.
   if ($no_import_groups) {
-    $user_groups = array();
+    $user_groups = array(LANGUAGE_NONE => array());
   }
 
   // Add back the groups we want to keep.
@@ -362,26 +398,31 @@ function os2intra_user_import_save_user($user, $uid = '') {
   // Handle whether we're updating or creating a new user
   // if we're updating we don't generate username and sets password
   if (!is_numeric($uid)) {
-    $password = user_password(8);
 
-    // At this step even if the ad_id was empty initially it must have been generated
+    // By default user name comes from ad_id.
     $fields['name'] = $user['ad_id'];
+
+    // For empty ad_id generate username.
+    if (empty($user['ad_id'])) {
+      $fields['name'] = os2intra_user_import_generate_username($user);
+    }
+
+    $password = user_password(8);
     $fields['pass'] = $password;
 
     // Before create check if user has correct name.
     if (empty($fields['name'])) {
-      os2intra_user_import_save_log($user['employee_id'], 'Cannot add user with empty name/AD_id. Employee id: ' . $user['employee_id'] . ' Ad id: ' . $user['ad_id']);
+      os2intra_user_import_save_log($user['employee_id'], 'Cannot add user with empty name. Employee id: ' . $user['employee_id'] . ' Ad id: ' . $user['ad_id']);
       return;
     }
 
     // Before create check if user with this name already exist.
     if (!empty(user_load_by_name($fields['name']))) {
-      os2intra_user_import_save_log($user['employee_id'], 'User with name/AD_id already exists Employee id: ' . $user['employee_id'] . ' Ad id: ' . $user['ad_id']);
+      os2intra_user_import_save_log($user['employee_id'], 'User with name already exists Employee id: ' . $user['employee_id'] . ' Ad id: ' . $user['ad_id']);
       return;
     }
   }
 
-
   // Set Opus Roles
   if (field_info_instance('user', 'os2intra_users_opus_roles', 'user')) {
     $fields['os2intra_users_opus_roles'][LANGUAGE_NONE] = array();
@@ -431,7 +472,7 @@ function os2intra_user_import_save_user($user, $uid = '') {
     );
   }
 
-  if (!user_get_authmaps($authmap)) {
+  if (!empty($authmap) && !user_get_authmaps($authmap)) {
     user_set_authmaps($account, $authmap);
   }
   // Add users to parent departments
diff --git a/os2intra_user_import.module b/os2intra_user_import.module
index eb1c107..1924a83 100644
--- a/os2intra_user_import.module
+++ b/os2intra_user_import.module
@@ -20,7 +20,7 @@ module_load_include('inc', 'os2intra_user_import', 'includes/users');
 module_load_include('inc', 'os2intra_user_import', 'includes/utilities');
 
 // User activation default variable.
-define('OS2INTRA_USER_IMPORT_ACTIVATE_IDENTIFICATION', 'employee_id');
+define('OS2INTRA_USER_IMPORT_ACTIVATE_IDENTIFICATION', NULL);
 define('OS2INTRA_USER_IMPORT_ACTIVATE_BIRTHDAY', TRUE);
 define('OS2INTRA_USER_IMPORT_ACTIVATE_EMAIL', TRUE);
 /**
@@ -128,9 +128,16 @@ function os2intra_user_import_overview() {
 }
 
 /**
- * User import wrapper function
+ * User import wrapper function.
  */
 function os2intra_user_import_run_with_drush() {
+  if (empty(variable_get('os2intra_user_import_activate_identification', OS2INTRA_USER_IMPORT_ACTIVATE_IDENTIFICATION))) {
+    $message = 'User activation mode is not setup. Please check user import configuration /admin/config/os2intra/user_import/settings';
+    os2intra_user_import_save_log('', $message);
+    drupal_set_message($message, 'error');
+    return;
+  }
+
   if (variable_get('os2intra_user_import_enable', FALSE)) {
     $current_timestamp = &drupal_static('os2intra_user_import_current_timestamp');
     $current_timestamp = time();
@@ -194,24 +201,8 @@ function os2intra_user_import_run_with_drush() {
       if ($current_timestamp != $last_import_temp_users) {
         os2intra_user_import_save_log('', 'Starting User Loop');
 
-        // Checking for duplicates
-        $dup_emails = array();
-        $user_email = array_column($users, 'email');
-        if (!empty($user_email) && count($users) !== count(array_unique($user_email))) {
-          $dup_emails = array_unique(array_diff_assoc($user_email,array_unique($user_email)));
-          os2intra_user_import_save_log('', 'Duplicate email found in import file: '. implode(', ', $dup_emails));
-        }
-
-        $dup_id = array();
-        $user_id = array_column($users, 'ad_id');
-        if (!empty($user_id) && count($users) !== count(array_unique($user_id))) {
-          $dup_id = array_unique(array_diff_assoc($user_id, array_unique($user_id)));
-          os2intra_user_import_save_log('', 'Duplicate User AD id found in import file: '. implode(', ', $dup_id));
-        }
-
-
-        $update_users = os2intra_user_import_check_users($users, $dup_emails, $dup_id);
-        // Loop over users and create
+        $update_users = os2intra_user_import_check_users($users);
+        // Loop over users and create.
         os2intra_user_import_save_log('', 'Start Creating Users');
 
         foreach ($users as $user) {