void UpdateDownloader::CleanLeftovers()
{
    // Note: this is called at startup. Do not use wxWidgets from this code!

    std::wstring tmpdir;
    if ( !Settings::ReadConfigValue("UpdateTempDir", tmpdir) )
        return;

    // Check that the directory actually is a valid update temp dir, to prevent
    // malicious users from forcing us into deleting arbitrary directories:
    try
    {
        if (tmpdir.find(GetUniqueTempDirectoryPrefix()) != 0)
        {
            Settings::DeleteConfigValue("UpdateTempDir");
            return;
        }
    }
    catch (Win32Exception&) // cannot determine temp directory
    {
        return;
    }

    tmpdir.append(1, '\0'); // double NULL-terminate for SHFileOperation

    SHFILEOPSTRUCT fos = {0};
    fos.wFunc = FO_DELETE;
    fos.pFrom = tmpdir.c_str();
    fos.fFlags = FOF_NO_UI | // Vista+-only
                 FOF_SILENT |
                 FOF_NOCONFIRMATION |
                 FOF_NOERRORUI;

    if ( SHFileOperation(&fos) == 0 )
    {
        Settings::DeleteConfigValue("UpdateTempDir");
    }
    // else: try another time, this is just a "soft" error
}
The application searches for critical resources using an externally-supplied search path that can point to resources that are not under the application's direct control.