So, let's recapitulate.

- You start Emacs 27.0.50
- In your init file(s), you do not change the default value of w32-pass-lwindow-to-system
- While Emacs has the focus, if you press an lwindow combination, Emacs catches it and it is not passed back to Windows.
- So, from inside 27.0.50, you cannot do LWin+R o LWin+D, etc.
- But this didn't happen with Emacs 26.2.

> Am I right now?

   Yes, you are right.

If so, when you're inside Emacs 27.0.50, what does it say when you examine the value of w32-pass-lwindow-to-system? For example, with describe-variable.

Does still happen if you start Emacs with 

   emacs -Q

C:\emacs-27.0.50-snapshot-2019-09-18-x86_64\bin>emacs -Q

------------------ 原始邮件 ------------------
发件人: "Juanma Barranquero"<lekktu@gmail.com>;
发送时间: 2019年9月25日(星期三) 凌晨1:17
收件人: "Albert"<georgealbert@qq.com>;
抄送: "Eli Zaretskii"<eliz@gnu.org>;"37495"<37495@debbugs.gnu.org>;
主题: Re: bug#37495: 27.0.50; lwindow doesn't pass to system


On Tue, Sep 24, 2019 at 6:59 PM Albert <georgealbert@qq.com> wrote:

> I'm sorry, the default value of w32-pass-lwindow-to-system is t. I dont' change w32-pass-lwindow-to-system in init file.

So, let's recapitulate.

- You start Emacs 27.0.50
- In your init file(s), you do not change the default value of w32-pass-lwindow-to-system
- While Emacs has the focus, if you press an lwindow combination, Emacs catches it and it is not passed back to Windows.
- So, from inside 27.0.50, you cannot do LWin+R o LWin+D, etc.
- But this didn't happen with Emacs 26.2.

Am I right now?

If so, when you're inside Emacs 27.0.50, what does it say when you examine the value of w32-pass-lwindow-to-system? For example, with describe-variable.

Does still happen if you start Emacs with 

   emacs -Q

?