diff --git a/hyperglass/configuration/main.py b/hyperglass/configuration/main.py
index 1ee5542..050e1c9 100644
--- a/hyperglass/configuration/main.py
+++ b/hyperglass/configuration/main.py
@@ -54,7 +54,9 @@ CONFIG_FILES = (
 
 def _check_config_files(directory: Path):
     """Verify config files exist and are readable."""
+
     files = ()
+
     for file in CONFIG_FILES:
         file_name, required = file
         file_path = directory / file_name
@@ -70,7 +72,7 @@ def _check_config_files(directory: Path):
                 + "Defaults will be used.",
                 f=str(file_path),
             )
-        files += (file_path,)
+        files += (checked,)
 
     return files
 
@@ -97,8 +99,10 @@ def _config_required(config_path: Path) -> Dict:
 
 def _config_optional(config_path: Path) -> Dict:
 
+    config = {}
+
     if config_path is None:
-        config = {}
+        return config
 
     else:
         try:
diff --git a/hyperglass/util/__init__.py b/hyperglass/util/__init__.py
index 1c3bd67..5171cc7 100644
--- a/hyperglass/util/__init__.py
+++ b/hyperglass/util/__init__.py
@@ -65,8 +65,9 @@ def check_path(
             else:
                 raise FileNotFoundError(f"{str(path)} does not exist.")
 
-        with path.open(mode):
-            result = path
+        if path.exists():
+            with path.open(mode):
+                result = path
 
     except Exception:
         result = None
@@ -517,7 +518,7 @@ async def build_frontend(  # noqa: C901
     params: Dict,
     app_path: Path,
     force: bool = False,
-):
+) -> bool:
     """Perform full frontend UI build process.
 
     Securely creates temporary file, writes frontend configuration