diff --git a/dashboard/src/components/BackupDialog.vue b/dashboard/src/components/BackupDialog.vue
index bc087e61a..75dc602af 100644
--- a/dashboard/src/components/BackupDialog.vue
+++ b/dashboard/src/components/BackupDialog.vue
@@ -22,6 +22,7 @@ const oldFormat = ref('');
 const providerConfig = ref({
   limits: {},
   mountOptions: {},
+  prefix: '',
 });
 
 async function onSubmit() {