diff --git a/xarray_ecmwf/engine_ecmwf.py b/xarray_ecmwf/engine_ecmwf.py
index c495f02..ad55cec 100644
--- a/xarray_ecmwf/engine_ecmwf.py
+++ b/xarray_ecmwf/engine_ecmwf.py
@@ -122,7 +122,9 @@ def cached_empty_dataset(self, request: dict[str, Any]) -> Iterator[xr.Dataset]:
 
         if not os.path.exists(path):
             with self.retrieve(request, override_cache_file=True) as read_ds:
-                read_ds.to_zarr(path, compute=False)
+                # check again as the retrieve may be long
+                if not os.path.exists(path):
+                    read_ds.to_zarr(path, compute=False)
         yield xr.open_dataset(path, engine="zarr")