diff --git a/Tools/msi/msi.py b/Tools/msi/msi.py
index 84215a1..63b2399 100644
--- a/Tools/msi/msi.py
+++ b/Tools/msi/msi.py
@@ -402,7 +402,7 @@
               ("VerdanaRed9", "Verdana", 9, 255, 0),
              ])
 
-    compileargs = r'-Wi "[TARGETDIR]Lib\compileall.py" -f -x bad_coding|badsyntax|site-packages|py3_ "[TARGETDIR]Lib"'
+    compileargs = r'-Wi "[TARGETDIR]Lib\compileall.py" -f -x "bad_coding|badsyntax|site-packages|py3_" "[TARGETDIR]Lib"'
     lib2to3args = r'-c "import lib2to3.pygram, lib2to3.patcomp;lib2to3.patcomp.PatternCompiler()"'
     # See "CustomAction Table"
     add_data(db, "CustomAction", [