diff --git a/urumanifest/commit.py b/urumanifest/commit.py
index 8538a4f..5e3259d 100644
--- a/urumanifest/commit.py
+++ b/urumanifest/commit.py
@@ -63,7 +63,7 @@ def _hash_asset(args: Tuple[Path, Path, bool]) -> Tuple[Path, str, int]:
         bundle_name = source_path.stem
         # Guess the executable path - we could get the exact name if we could unpack the Info.plist
         # in a cross platform way.
-        source_path = source_path.joinpath("Contents", MacOS", bundle_name)
+        source_path = source_path.joinpath("Contents", "MacOS", bundle_name)
     with source_path.open("rb") as in_stream:
         _io_loop(in_stream, h.update)
     return server_path, h.hexdigest(), source_path.stat().st_size