diff --git a/frontend/src/components/FileExplorer.tsx b/frontend/src/components/FileExplorer.tsx
index 7ae16a8..2f4e537 100644
--- a/frontend/src/components/FileExplorer.tsx
+++ b/frontend/src/components/FileExplorer.tsx
@@ -938,10 +938,10 @@ export default function FileExplorer({ onLogout }: FileExplorerProps) {
         const uploadPath = path ? (destPath === '.' ? path : `${destPath}/${path}`) : destPath;
         
         try {
-          if (newBatch.abortController.signal.aborted) throw new Error('Upload canceled');
+          if (newBatch.abortController?.signal?.aborted) throw new Error('Upload canceled');
           await api.upload(file, uploadPath, {
             overwrite,
-            signal: newBatch.abortController.signal,
+            signal: newBatch.abortController?.signal,
             onProgress: (percent) => {
               fileProgressMap.set(file.name + path, (percent / 100) * file.size);
               updateProgress();