diff --git a/importlib_metadata/__init__.py b/importlib_metadata/__init__.py
index 3c4e0a25..47cae5eb 100644
--- a/importlib_metadata/__init__.py
+++ b/importlib_metadata/__init__.py
@@ -538,7 +538,11 @@ def _read_files_egginfo_installed(self):
             return
 
         ret = [
-            str((subdir / line).resolve().relative_to(self.locate_file('').resolve()))
+            str(
+                pathlib.PosixPath(subdir / line)
+                .resolve()
+                .relative_to(self.locate_file('').resolve())
+            )
             for line in text.splitlines()
         ]
         return map('"{}"'.format, ret)