- delay the restart action from the error pane until after everything has been shut down.

This cannot be done from a place where the old instance still can write to the config file, which happens only in the shutdown process.

src/common/platform/win32/i_main.cpp

@@ -545,6 +545,20 @@ LRESULT CALLBACK LConProc (HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
 //
 //==========================================================================
 
+bool restartrequest;
+
+void CheckForRestart()
+{
+	if (restartrequest)
+	{
+		HMODULE hModule = GetModuleHandleW(NULL);
+		WCHAR path[MAX_PATH];
+		GetModuleFileNameW(hModule, path, MAX_PATH);
+		ShellExecuteW(NULL, L"open", path, GetCommandLineW(), NULL, SW_SHOWNORMAL);
+	}
+	restartrequest = false;
+}
+
 INT_PTR CALLBACK ErrorPaneProc (HWND hDlg, UINT msg, WPARAM wParam, LPARAM lParam)
 {
 	switch (msg)
@@ -559,11 +573,7 @@ INT_PTR CALLBACK ErrorPaneProc (HWND hDlg, UINT msg, WPARAM wParam, LPARAM lPara
 		{
 			if (LOWORD(wParam) == IDC_BUTTON1) // we pressed the restart button, so run GZDoom again
 			{
-				HMODULE hModule = GetModuleHandleW(NULL);
-				WCHAR path[MAX_PATH];
-				GetModuleFileNameW(hModule, path, MAX_PATH);
-
-				ShellExecuteW(NULL, L"open", path, GetCommandLineW(), NULL, SW_SHOWNORMAL);
+				restartrequest = true;
 			}
 			PostQuitMessage (0);
 			return TRUE;

src/d_main.cpp

@@ -3716,6 +3716,10 @@ int GameMain()
 	DeleteStartupScreen();
 	delete Args;
 	Args = nullptr;
+#ifdef _WIN32
+	void CheckForRestart();
+	CheckForRestart();
+#endif
 	return ret;
 }