diff --git a/win/rfb_win32/Registry.cxx b/win/rfb_win32/Registry.cxx
index 963a36a..9cd5018 100644
--- a/win/rfb_win32/Registry.cxx
+++ b/win/rfb_win32/Registry.cxx
@@ -254,7 +254,7 @@
       TCharArray result(required);
       length = ExpandEnvironmentStrings(str.buf, result.buf, required);
       if (required<length)
-        rdr::Exception("unable to expand environment strings");
+        throw rdr::Exception("unable to expand environment strings");
       return result.takeBuf();
     } else {
       return tstrDup(_T(""));