diff --git a/setup/extensions.json b/setup/extensions.json
index c80e52bf47..f5e9067989 100644
--- a/setup/extensions.json
+++ b/setup/extensions.json
@@ -139,7 +139,7 @@
     {
         "name": "winutil",
         "only": "windows",
-        "sources": "calibre/utils/windows/winutilpp.cpp",
+        "sources": "calibre/utils/windows/winutil.cpp",
         "libraries": "shell32 wininet advapi32",
         "cflags": "/X"
     },
diff --git a/src/calibre/utils/windows/winutilpp.cpp b/src/calibre/utils/windows/winutil.cpp
similarity index 100%
rename from src/calibre/utils/windows/winutilpp.cpp
rename to src/calibre/utils/windows/winutil.cpp