diff --git a/README.md b/README.md
index 44d89e8d..562fc5ea 100644
--- a/README.md
+++ b/README.md
@@ -39,10 +39,11 @@ Wine. All those differences are also documented on the
 Included bug fixes and improvements
 -----------------------------------
 
-**Bug fixes and features included in the next upcoming release [9]:**
+**Bug fixes and features included in the next upcoming release [10]:**
 
 * Add stub for winspool.SetPrinterW level 8 ([Wine Bug #24645](https://bugs.winehq.org/show_bug.cgi?id=24645))
 * Allow non-nullterminated string as working directory in kernel32.create_startup_info
+* Fallback to default comspec when %COMSPEC% is not set
 * Fix access violation in MSYS2 git when cloning repository
 * Fix error handling in DeferWindowPos when passing an invalid HWND ([Wine Bug #23187](https://bugs.winehq.org/show_bug.cgi?id=23187))
 * Fix failure to create anonymous file mapping after failed open_fd server call
diff --git a/debian/changelog b/debian/changelog
index 7c91845d..af851666 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -19,6 +19,8 @@ wine-staging (1.7.51) UNRELEASED; urgency=low
   * Added patch to fix SHFileOperation with FO_MOVE on Vista+ (should create
     non-existent subdirectories).
   * Added patch to silence repeated crypt32.CryptUnprotectMemory FIXMEs.
+  * Added patch to fallback to default comspec when %COMSPEC% is not set (fixes
+    Wine Staging Bug #405).
   * Removed patch to fix bug in wineserver debug_children inheritance (accepted
     upstream).
   * Removed patch to use helper function for NtWaitForMultipleObjects and
diff --git a/patches/kernel32-COMSPEC/0001-kernel32-Fallback-to-default-comspec-when-COMSPEC-is.patch b/patches/kernel32-COMSPEC/0001-kernel32-Fallback-to-default-comspec-when-COMSPEC-is.patch
new file mode 100644
index 00000000..87749d88
--- /dev/null
+++ b/patches/kernel32-COMSPEC/0001-kernel32-Fallback-to-default-comspec-when-COMSPEC-is.patch
@@ -0,0 +1,61 @@
+From be12a69b9edfbbb091450a42a4408bc5579d1d27 Mon Sep 17 00:00:00 2001
+From: Qian Hong <qhong@codeweavers.com>
+Date: Sun, 26 Jul 2015 17:55:01 +0800
+Subject: kernel32: Fallback to default comspec when %COMSPEC% is not set.
+
+---
+ dlls/kernel32/process.c |  6 +++++-
+ programs/cmd/wcmdmain.c | 10 ++++++++++
+ 2 files changed, 15 insertions(+), 1 deletion(-)
+
+diff --git a/dlls/kernel32/process.c b/dlls/kernel32/process.c
+index b0c06e3..caa005c 100644
+--- a/dlls/kernel32/process.c
++++ b/dlls/kernel32/process.c
+@@ -2174,13 +2174,17 @@ static BOOL create_cmd_process( LPCWSTR filename, LPWSTR cmd_line, LPVOID env, L
+ 
+ {
+     static const WCHAR comspecW[] = {'C','O','M','S','P','E','C',0};
++    static const WCHAR cmdW[] = {'\\','c','m','d','.','e','x','e',0};
+     static const WCHAR slashcW[] = {' ','/','c',' ',0};
+     WCHAR comspec[MAX_PATH];
+     WCHAR *newcmdline;
+     BOOL ret;
+ 
+     if (!GetEnvironmentVariableW( comspecW, comspec, sizeof(comspec)/sizeof(WCHAR) ))
+-        return FALSE;
++    {
++        GetSystemDirectoryW( comspec, (sizeof(comspec) - sizeof(cmdW))/sizeof(WCHAR) );
++        strcatW( comspec, cmdW );
++    }
+     if (!(newcmdline = HeapAlloc( GetProcessHeap(), 0,
+                                   (strlenW(comspec) + 4 + strlenW(cmd_line) + 1) * sizeof(WCHAR))))
+         return FALSE;
+diff --git a/programs/cmd/wcmdmain.c b/programs/cmd/wcmdmain.c
+index 7666329..b0ec82f 100644
+--- a/programs/cmd/wcmdmain.c
++++ b/programs/cmd/wcmdmain.c
+@@ -2340,10 +2340,20 @@ int wmain (int argc, WCHAR *argvW[])
+   static const WCHAR offW[] = {'O','F','F','\0'};
+   static const WCHAR promptW[] = {'P','R','O','M','P','T','\0'};
+   static const WCHAR defaultpromptW[] = {'$','P','$','G','\0'};
++  static const WCHAR comspecW[] = {'C','O','M','S','P','E','C',0};
++  static const WCHAR cmdW[] = {'\\','c','m','d','.','e','x','e',0};
++  WCHAR comspec[MAX_PATH];
+   CMD_LIST *toExecute = NULL;         /* Commands left to be executed */
+   OSVERSIONINFOW osv;
+   char osver[50];
+ 
++  if (!GetEnvironmentVariableW(comspecW, comspec, sizeof(comspec)/sizeof(WCHAR)))
++  {
++      GetSystemDirectoryW(comspec, (sizeof(comspec) - sizeof(cmdW))/sizeof(WCHAR));
++      strcatW(comspec, cmdW);
++      SetEnvironmentVariableW(comspecW, comspec);
++  }
++
+   srand(time(NULL));
+ 
+   /* Get the windows version being emulated */
+-- 
+2.5.0
+
diff --git a/patches/kernel32-COMSPEC/definition b/patches/kernel32-COMSPEC/definition
new file mode 100644
index 00000000..3cfee92c
--- /dev/null
+++ b/patches/kernel32-COMSPEC/definition
@@ -0,0 +1 @@
+Fixes: Fallback to default comspec when %COMSPEC% is not set
diff --git a/patches/patchinstall.sh b/patches/patchinstall.sh
index 9121605f..e2155d0c 100755
--- a/patches/patchinstall.sh
+++ b/patches/patchinstall.sh
@@ -145,6 +145,7 @@ patch_enable_all ()
 	enable_inetcpl_Default_Home="$1"
 	enable_iphlpapi_System_Ping="$1"
 	enable_iphlpapi_TCP_Table="$1"
+	enable_kernel32_COMSPEC="$1"
 	enable_kernel32_CompareStringEx="$1"
 	enable_kernel32_CopyFileEx="$1"
 	enable_kernel32_Cwd_Startup_Info="$1"
@@ -520,6 +521,9 @@ patch_enable ()
 		iphlpapi-TCP_Table)
 			enable_iphlpapi_TCP_Table="$2"
 			;;
+		kernel32-COMSPEC)
+			enable_kernel32_COMSPEC="$2"
+			;;
 		kernel32-CompareStringEx)
 			enable_kernel32_CompareStringEx="$2"
 			;;
@@ -3170,6 +3174,18 @@ if test "$enable_iphlpapi_TCP_Table" -eq 1; then
 	) >> "$patchlist"
 fi
 
+# Patchset kernel32-COMSPEC
+# |
+# | Modified files:
+# |   *	dlls/kernel32/process.c, programs/cmd/wcmdmain.c
+# |
+if test "$enable_kernel32_COMSPEC" -eq 1; then
+	patch_apply kernel32-COMSPEC/0001-kernel32-Fallback-to-default-comspec-when-COMSPEC-is.patch
+	(
+		echo '+    { "Qian Hong", "kernel32: Fallback to default comspec when %COMSPEC% is not set.", 1 },';
+	) >> "$patchlist"
+fi
+
 # Patchset kernel32-CompareStringEx
 # |
 # | Modified files: