diff --git a/components/IscnUploadForm.vue b/components/IscnUploadForm.vue
index 2f7a831f..16e298ab 100644
--- a/components/IscnUploadForm.vue
+++ b/components/IscnUploadForm.vue
@@ -709,7 +709,9 @@ export default class UploadForm extends Vue {
         this.sentArweaveTransactionInfo.set(records.ipfsHash, { ...uploadedData, arweaveId });
         if (tempRecord.fileName.includes('cover.jpeg')) {
           const metadata = this.epubMetadataList.find((file: any) => file.ipfsHash === records.ipfsHash)
-          metadata.thumbnailUrl = arweaveId
+          if (metadata && metadata.thumbnailUrl) {
+            metadata.thumbnailUrl = arweaveId
+          }
         }
         this.$emit('arweaveUploaded', { arweaveId })
         this.isOpenSignDialog = false