diff --git a/aksetup_helper.py b/aksetup_helper.py
index 755b0bc404405f654765ad712e739939f1a27762..42ea8cd9caa63e03e8046b4fefd002b7eb1866a5 100644
--- a/aksetup_helper.py
+++ b/aksetup_helper.py
@@ -565,7 +565,7 @@ def set_up_shipped_boost_if_requested(conf):
                 if not f.startswith("bpl-subset/bpl_subset/libs/thread/src")]
 
         import sys
-        if sys.platform == "nt":
+        if sys.platform == "win32":
             source_files += glob(
                     "bpl-subset/bpl_subset/libs/thread/src/win32/*.cpp")
         else: