From 2c0cf894f430943c3ea36ca89f2f7ebe8e68a2c6 Mon Sep 17 00:00:00 2001
From: Eli Zaretskii <eliz@gnu.org>
Date: Thu, 2 Oct 2025 10:22:37 +0300
Subject: [PATCH] Fix 'restart-emacs' on MS-Windows

* src/w32.c (w32_reexec_emacs): Reset undocumented bits in
STARTUPINFO flags.  Suggested by yhr0x43 <yhr0x43@gmail.com>.
(Bug#79554)
---
 src/w32.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/w32.c b/src/w32.c
index 7182bee0ab7..d9fee5b6f03 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -10939,6 +10939,9 @@ w32_reexec_emacs (char *cmd_line, const char *wdir)
   DWORD dwCreationFlags = NORMAL_PRIORITY_CLASS;
 
   GetStartupInfo (&si);		/* Use the same startup info as the caller.  */
+  /* Reset undocumented bits in STARTUPINFO flags, as they could cause a
+     crash in the re-exec'ed Emacs.  */
+  si.dwFlags &= 0xbbff;	/* reset the 0x4000 and 0x0400 bits */
   if (inhibit_window_system)
     {
       HANDLE screen_handle;