diff --git a/s3file/middleware.py b/s3file/middleware.py
index 1d3a45d..ea8943a 100644
--- a/s3file/middleware.py
+++ b/s3file/middleware.py
@@ -30,7 +30,7 @@ def get_files_from_storage(paths):
         for path in paths:
             path = pathlib.PurePosixPath(path)
             try:
-                f = storage.open(path.relative_to(storage.location))
+                f = storage.open(str(path.relative_to(storage.location)))
                 f.name = path.name
                 yield f
             except (OSError, ValueError):