diff --git a/mercurial/templater.py b/mercurial/templater.py
--- a/mercurial/templater.py
+++ b/mercurial/templater.py
@@ -1107,5 +1107,5 @@ def open_template(name, templatepath=Non
                 name,
                 resourceutil.open_resource(package_name, name_parts[-1]),
             )
-        except (ModuleNotFoundError, FileNotFoundError):
+        except (ImportError, OSError):
             return None, None