diff --git a/application/Espo/Repositories/Attachment.php b/application/Espo/Repositories/Attachment.php
index 0d9cad641e..e46d8c2aa0 100644
--- a/application/Espo/Repositories/Attachment.php
+++ b/application/Espo/Repositories/Attachment.php
@@ -69,13 +69,19 @@ class Attachment extends \Espo\Core\Repositories\Database implements
         parent::beforeSave($entity, $options);
 
         $storage = $entity->get('storage');
+
         if (!$storage) {
             $entity->set('storage', $this->config->get('defaultFileStorage', null));
         }
 
         if ($entity->isNew()) {
             if (!$entity->has('size') && $entity->has('contents')) {
-                $entity->set('size', mb_strlen($entity->get('contents')));
+                $contents = $entity->get('contents');
+
+                $entity->set(
+                    'size',
+                    mb_strlen($contents, '8bit')
+                );
             }
         }
     }
diff --git a/package-lock.json b/package-lock.json
index 9e95329369..dc6ce95de3 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "espocrm",
-  "version": "6.1.2",
+  "version": "6.1.3",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 78b797ec04..caca0c4b4e 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "espocrm",
-  "version": "6.1.2",
+  "version": "6.1.3",
   "description": "",
   "main": "index.php",
   "repository": {