diff --git a/corrlib/input/openQCD.py b/corrlib/input/openQCD.py
index 9dfe85f..8f5a8a1 100644
--- a/corrlib/input/openQCD.py
+++ b/corrlib/input/openQCD.py
@@ -31,6 +31,8 @@ def load_ms1_infile(path: Path, project: str, file_in_project: str) -> dict[str,
     """
 
     file = os.path.join(path, "projects", project, file_in_project)
+    if not os.path.exists(file):
+        raise IOError(f"File {file} does not exist.")
     ds = os.path.join(path, "projects", project)
     dl.get(file, dataset=ds)
     with open(file, 'r') as fp: