diff --git a/src/main/knowledge/preprocess/MineruPreprocessProvider.ts b/src/main/knowledge/preprocess/MineruPreprocessProvider.ts
index afc19ae34a..a86b3cc610 100644
--- a/src/main/knowledge/preprocess/MineruPreprocessProvider.ts
+++ b/src/main/knowledge/preprocess/MineruPreprocessProvider.ts
@@ -273,7 +273,7 @@ export default class MineruPreprocessProvider extends BasePreprocessProvider {
 
       const response = await fetch(uploadUrl, {
         method: 'PUT',
-        body: fileBuffer,
+        body: new Uint8Array(fileBuffer),
         headers: {
           'Content-Type': 'application/pdf'
         }