diff --git a/radicale/__init__.py b/radicale/__init__.py
index 870bf369..b8d864f9 100644
--- a/radicale/__init__.py
+++ b/radicale/__init__.py
@@ -53,9 +53,14 @@ def _get_application_instance(config_path: str, wsgi_errors: types.ErrorStream
                     config_path))
                 log.set_level(cast(str, configuration.get("logging", "level")))
                 # Log configuration after logger is configured
+                default_config_active = True
                 for source, miss in configuration.sources():
-                    logger.info("%s %s", "Skipped missing" if miss
+                    logger.info("%s %s", "Skipped missing/unreadable" if miss
                                 else "Loaded", source)
+                    if not miss and source != "default config":
+                        default_config_active = False
+                if default_config_active:
+                    logger.warn("%s", "No config file found/readable - only default config is active")
                 _application_instance = Application(configuration)
     if _application_config_path != config_path:
         raise ValueError("RADICALE_CONFIG must not change: %r != %r" %
diff --git a/radicale/__main__.py b/radicale/__main__.py
index dcf8cb67..c9a022e1 100644
--- a/radicale/__main__.py
+++ b/radicale/__main__.py
@@ -167,8 +167,14 @@ def run() -> None:
     log.set_level(cast(str, configuration.get("logging", "level")))
 
     # Log configuration after logger is configured
+    default_config_active = True
     for source, miss in configuration.sources():
-        logger.info("%s %s", "Skipped missing" if miss else "Loaded", source)
+        logger.info("%s %s", "Skipped missing/unreadable" if miss else "Loaded", source)
+        if not miss and source != "default config":
+            default_config_active = False
+
+    if default_config_active:
+        logger.warn("%s", "No config file found/readable - only default config is active")
 
     if args_ns.verify_storage:
         logger.info("Verifying storage")