diff --git a/backend/api/audit.py b/backend/api/audit.py
index 040b163..a2aced8 100644
--- a/backend/api/audit.py
+++ b/backend/api/audit.py
@@ -217,6 +217,8 @@ async def download_daily_export(
         raise HTTPException(status_code=404, detail="Invalid date format")
 
     backend = get_storage_backend()
+    if not isinstance(backend, MinIOBackend):
+        raise HTTPException(status_code=404, detail="Export not found")
     key = f"audit-logs/{date}.csv"
 
     def _get() -> bytes: