When you check this box, the utility uses a different API. Instead of using SOLIDWORKS' "Save" function, the utility performs a " Save As" operation, replacing the existing file.

In fact, in some cases on Windows, when you save a file using the same name, its size appears to increase abnormally (this is true for all software on Windows). The trick, therefore, is to use “ Save As” with a different name; this can reduce the file size (though it doesn’t always work!). Checking this option automates this process.