diff --git a/tools/python/jwutils/stree/serdes.py b/tools/python/jwutils/stree/serdes.py
index b47db38..1249f86 100644
--- a/tools/python/jwutils/stree/serdes.py
+++ b/tools/python/jwutils/stree/serdes.py
@@ -88,18 +88,16 @@ def _read_lines_from_one_path(path: str, throw=True, level=0, log_prio=INFO, pat
                             include_path = dir_name + '/' + include_path
                     include_lines = _read_lines(include_path, throw=(not optional), level=level+1, paths_buf=paths_buf)
                     if include_lines is None:
-                        msg = f'{path}: Failed to process "{line}"'
-                        slog(DEBUG, line)
+                        slog(DEBUG, f'{path}: Failed to process "{line}"')
                         continue
                     ret.extend(include_lines)
                     continue
                 ret.append(line)
             return ret
     except Exception as e:
-        msg = f'Failed to read file "{path}": {e}'
-        if throw:
-            raise Exception(msg)
-        slog(DEBUG, msg)
+        slog(ERR, f'Failed to read file "{path}": {str(e)}')
+        if throw or not isinstance(e, FileNotFoundError):
+            raise
     return None
 
 def _read_lines(path: str, throw=True, level=0, log_prio=INFO, paths_buf=None):