diff --git a/lib/clouddrop-upload.js b/lib/clouddrop-upload.js
index fe1aafb..56fe3d3 100644
--- a/lib/clouddrop-upload.js
+++ b/lib/clouddrop-upload.js
@@ -190,20 +190,25 @@ class ClouddropUploader {
       try { fs.closeSync(fd); } catch {}
     }
 
-    // 3. Complete session
-    const completeRes = await request(`${API_BASE}/upload/${sessionId}/complete`, {
-      method: 'POST',
-      dispatcher: clouddropAgent,
-      signal,
-      headers: this._headers({ 'Content-Type': 'application/json' }),
-      body: '{}',
-      headersTimeout: COMPLETE_TIMEOUT,
-      bodyTimeout: COMPLETE_TIMEOUT
-    });
-    const completePayload = await this._parseJsonResponse(completeRes);
-    const fileId = completePayload.fileId || completePayload.id;
-    if (!fileId) throw new Error('Clouddrop: Keine fileId in /upload/complete Antwort');
-    return fileId;
+    // 3. Complete session — all bytes are already on the server at this point.
+    // We MUST NOT throw here, otherwise the upload-manager would retry the entire
+    // multi-GB upload. Any failure (timeout, non-JSON, missing fileId, server still
+    // post-processing) is swallowed and we fall back to sessionId as file_code.
+    try {
+      const completeRes = await request(`${API_BASE}/upload/${sessionId}/complete`, {
+        method: 'POST',
+        dispatcher: clouddropAgent,
+        signal,
+        headers: this._headers({ 'Content-Type': 'application/json' }),
+        body: '{}',
+        headersTimeout: COMPLETE_TIMEOUT,
+        bodyTimeout: COMPLETE_TIMEOUT
+      });
+      const completePayload = await this._parseJsonResponse(completeRes).catch(() => ({}));
+      return completePayload.fileId || completePayload.id || sessionId;
+    } catch {
+      return sessionId;
+    }
   }
 
   /**