diff --git a/backend/lib/dataTransfer/index.js b/backend/lib/dataTransfer/index.js
index 6f62d97..5dc57bb 100644
--- a/backend/lib/dataTransfer/index.js
+++ b/backend/lib/dataTransfer/index.js
@@ -122,6 +122,8 @@ function cleanupUploads(dir, { maxAgeMs = 24 * 60 * 60 * 1000 } = {}) {
       const file = path.join(dir, name)
       try {
         const stat = fs.statSync(file)
+        /* 只删普通文件：目录里还套着 multer 的 uploads/，别把目录本身当过期文件删 */
+        if (!stat.isFile()) continue
         if (Date.now() - stat.mtimeMs > maxAgeMs) { fs.unlinkSync(file); removed++ }
       } catch { /* 单个文件失败不影响其它清理 */ }
     }
diff --git a/backend/routes/dataTransfer.js b/backend/routes/dataTransfer.js
index 5b68933..ca9881a 100644
--- a/backend/routes/dataTransfer.js
+++ b/backend/routes/dataTransfer.js
@@ -121,6 +121,8 @@ router.post('/import/preview', guard, upload.single('file'), async (req, res) =>
     fs.renameSync(req.file.path, target)
     /* 顺手清掉 24 小时前的旧包，避免上传目录无限增长（本次刚移入的 mtime 是现在，不会被删） */
     transfer.cleanupUploads(TRANSFER_DIR)
+    /* multer 落盘后因体积/字段错误被丢弃的残片留在 uploads/，一并清 */
+    transfer.cleanupUploads(UPLOAD_DIR)
 
     const categories = parseCategories(req.body?.categories)
     const preview = await transfer.previewImport(db, target, {