diff --git a/.actions/setup_tools.py b/.actions/setup_tools.py
index 5801e1497a..2790820a5a 100644
--- a/.actions/setup_tools.py
+++ b/.actions/setup_tools.py
@@ -26,7 +26,9 @@ _PACKAGE_MAPPING = {"pytorch": "pytorch_lightning", "app": "lightning_app"}
 
 def _load_py_module(name: str, location: str) -> ModuleType:
     spec = spec_from_file_location(name, location)
+    assert spec, f"Failed to load module {name} from {location}"
     py = module_from_spec(spec)
+    assert spec.loader, f"ModuleSpec.loader is None for {name} from {location}"
     spec.loader.exec_module(py)
     return py
 
diff --git a/pyproject.toml b/pyproject.toml
index dc9db77d6d..51781d4953 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -95,6 +95,5 @@ module = [
     "pytorch_lightning.utilities.data",
     "pytorch_lightning.utilities.distributed",
     "pytorch_lightning.utilities.meta",
-    "pytorch_lightning.__setup__",
 ]
 ignore_errors = "True"
diff --git a/setup.py b/setup.py
index 0ff57c3f85..a542b3c1e0 100755
--- a/setup.py
+++ b/setup.py
@@ -74,7 +74,9 @@ with open(__file__, "w") as fp:
 
 def _load_py_module(name: str, location: str) -> ModuleType:
     spec = spec_from_file_location(name, location)
+    assert spec, f"Failed to load module {name} from {location}"
     py = module_from_spec(spec)
+    assert spec.loader, f"ModuleSpec.loader is None for {name} from {location}"
     spec.loader.exec_module(py)
     return py
 
diff --git a/src/lightning/__setup__.py b/src/lightning/__setup__.py
index f549419bf7..93679c2b88 100644
--- a/src/lightning/__setup__.py
+++ b/src/lightning/__setup__.py
@@ -15,7 +15,9 @@ _FREEZE_REQUIREMENTS = bool(int(os.environ.get("FREEZE_REQUIREMENTS", 0)))
 
 def _load_py_module(name: str, location: str) -> ModuleType:
     spec = spec_from_file_location(name, location)
+    assert spec, f"Failed to load module {name} from {location}"
     py = module_from_spec(spec)
+    assert spec.loader, f"ModuleSpec.loader is None for {name} from {location}"
     spec.loader.exec_module(py)
     return py
 
diff --git a/src/lightning_app/__setup__.py b/src/lightning_app/__setup__.py
index e989a17b50..2a738f20c6 100644
--- a/src/lightning_app/__setup__.py
+++ b/src/lightning_app/__setup__.py
@@ -14,7 +14,9 @@ _FREEZE_REQUIREMENTS = bool(int(os.environ.get("FREEZE_REQUIREMENTS", 0)))
 
 def _load_py_module(name: str, location: str) -> ModuleType:
     spec = spec_from_file_location(name, location)
+    assert spec, f"Failed to load module {name} from {location}"
     py = module_from_spec(spec)
+    assert spec.loader, f"ModuleSpec.loader is None for {name} from {location}"
     spec.loader.exec_module(py)
     return py
 
diff --git a/src/pytorch_lightning/__setup__.py b/src/pytorch_lightning/__setup__.py
index 4b28df6829..8fd93c77ee 100644
--- a/src/pytorch_lightning/__setup__.py
+++ b/src/pytorch_lightning/__setup__.py
@@ -15,7 +15,9 @@ _FREEZE_REQUIREMENTS = bool(int(os.environ.get("FREEZE_REQUIREMENTS", 0)))
 
 def _load_py_module(name: str, location: str) -> ModuleType:
     spec = spec_from_file_location(name, location)
+    assert spec, f"Failed to load module {name} from {location}"
     py = module_from_spec(spec)
+    assert spec.loader, f"ModuleSpec.loader is None for {name} from {location}"
     spec.loader.exec_module(py)
     return py