diff --git a/src/backend/app/config.py b/src/backend/app/config.py
index bb897b6ef9..9a90f8a523 100644
--- a/src/backend/app/config.py
+++ b/src/backend/app/config.py
@@ -125,7 +125,7 @@ def configure_s3_download_root(cls, v: Optional[str], info: ValidationInfo) -> s
         service name for S3_ENDPOINT instead.
         """
         # If set manually, pass through
-        if isinstance(v, str):
+        if isinstance(v, str) and v != "":
             return v
         # For dev setup
         dev_port = info.data.get("FMTM_DEV_PORT")