diff --git a/modflow_devtools/models.py b/modflow_devtools/models.py
index 32e17f2a..3beedbb6 100644
--- a/modflow_devtools/models.py
+++ b/modflow_devtools/models.py
@@ -115,6 +115,7 @@ def __init__(
             path = [Path(p).expanduser().resolve().absolute() for p in path]  # type: ignore
             missing = [p for p in path if not p.is_dir()]  # type: ignore
             if any(missing):
+                missing = [str(p) for p in missing]  # type: ignore
                 raise NotADirectoryError(
                     f"Directory paths not found: {', '.join(missing)}"  # type: ignore
                 )