diff --git a/composer.json b/composer.json
index 451825e..2b9057d 100644
--- a/composer.json
+++ b/composer.json
@@ -1,7 +1,7 @@
 {
     "name": "kiwilan/php-ebook",
     "description": "PHP package to read metadata and extract covers from eBooks (.epub, .cbz, .cbr, .cb7, .cbt, .pdf) and audiobooks (.mp3, .m4a, .m4b, .flac, .ogg).",
-    "version": "1.3.32",
+    "version": "1.3.33",
     "keywords": [
         "php",
         "ebook",
diff --git a/src/Tools/MetaTitle.php b/src/Tools/MetaTitle.php
index 768b562..83dda36 100644
--- a/src/Tools/MetaTitle.php
+++ b/src/Tools/MetaTitle.php
@@ -67,6 +67,7 @@ private function setMetaTitle(Ebook $ebook): static
         $this->slugLang = $this->generateSlug($title, $ebook->extension(), $language);
 
         $this->slugSortWithSerie = $this->generateSortSerie($title, $series, $volume, $language);
+        $this->uniqueFilename = $this->generateUniqueFilename($ebook);
 
         if (! $series) {
             return $this;
@@ -75,7 +76,6 @@ private function setMetaTitle(Ebook $ebook): static
         $this->serieSlug = $this->setSlug($series);
         $this->serieSlugSort = $this->generateSortTitle($series, $language);
         $this->serieSlugLang = $this->generateSlug($series, $ebook->extension(), $language);
-        $this->uniqueFilename = $this->generateUniqueFilename($ebook);
 
         return $this;
     }
@@ -212,14 +212,23 @@ private function generateSlug(string $title, ?string $type, ?string $language):
     private function generateUniqueFilename(Ebook $ebook): string
     {
         $author = $this->setSlug($ebook->authorMain());
-        $series = $this->setSlug($ebook->series());
-        $volume = (string) $ebook->volume();
-        $volume = $volume = strlen($volume) < 2 ? '0'.$volume : $volume;
+        $filename = "{$author}";
+        if ($ebook->series()) {
+            $series = $this->setSlug($ebook->series());
+            $filename .= "-{$series}";
+        }
+        if ($ebook->volume()) {
+            $volume = (string) $ebook->volume();
+            $volume = $volume = strlen($volume) < 2 ? '0'.$volume : $volume;
+            $filename .= "-{$volume}";
+        }
         $title = $this->setSlug($ebook->title());
+        $filename .= "-{$title}";
         $language = $this->setSlug($ebook->language());
+        $filename .= "-{$language}";
         $format = $this->setSlug($ebook->extension());
+        $filename .= "-{$format}";
 
-        $filename = "{$author}-{$series}-{$volume}-{$title}-{$language}-{$format}";
         $filename = $this->setSlug($filename);
 
         return $filename;
diff --git a/tests/EbookTest.php b/tests/EbookTest.php
index 122f9fa..6494a2b 100644
--- a/tests/EbookTest.php
+++ b/tests/EbookTest.php
@@ -41,6 +41,7 @@
 
     $metadata = $ebook->metadata();
     expect($metadata)->toBeInstanceOf(EbookMetadata::class);
+    expect($ebook->metaTitle()->uniqueFilename())->toBeString();
 
     if ($metadata->isEpub()) {
         expect($metadata->epub())->toBeInstanceOf(EpubMetadata::class);