diff --git a/lean/components/config/lean_config_manager.py b/lean/components/config/lean_config_manager.py
index f4892340..0a765922 100644
--- a/lean/components/config/lean_config_manager.py
+++ b/lean/components/config/lean_config_manager.py
@@ -98,11 +98,10 @@ def get_known_lean_config_paths(self) -> List[Path]:
         :return: a list of paths to Lean config files that were used in the past
         """
         lean_config_paths = self._cache_storage.get("known-lean-config-paths", [])
-        lean_config_paths = [Path(p) for p in lean_config_paths]
+        lean_config_paths = [Path(normcase(p)) for p in lean_config_paths if Path(p).is_file()]
         lean_config_paths = list(set(lean_config_paths))
-        lean_config_paths = [p for p in lean_config_paths if p.is_file()]
 
-        self._cache_storage.set("known-lean-config-paths", [normcase(p) for p in lean_config_paths])
+        self._cache_storage.set("known-lean-config-paths", [str(p) for p in lean_config_paths])
 
         return lean_config_paths