Finally, I’ve solved this problem.
Just in chance, I found some menu and changed the setting. After then the ‘Save Change Window’ pops up smoothly.
I share the action I’ve done.
But there are some things you must be aware.
At first, I don’t know there would be any side effect due to this action. In my case, I haven’t experienced any side effect until now. But I’m not sure unexpected thing would happen sometime.
And I use Korean version MS Word 2016. So I write translated menu side-by-side. But it might be not exactly same with real menu.