diff --git a/tljh/conda.py b/tljh/conda.py
index ee8568c..558c218 100644
--- a/tljh/conda.py
+++ b/tljh/conda.py
@@ -51,6 +51,8 @@ def download_miniconda_installer(installer_url, sha256sum):
     """
     with tempfile.NamedTemporaryFile('wb') as f:
         f.write(requests.get(installer_url).content)
+        f.flush()
+        os.fsync()
 
         if sha256_file(f.name) != sha256sum:
             raise Exception('sha256sum hash mismatch! Downloaded file corrupted')