Why Magic.TXD has dropped XP support:

We want to provide the best quality tool for our most capable users. But the Windows XP features destroyed many things (no SRW locks, separate CRT, ...). This is long after official MS support ended. Windows XP has always been dreaded by developers as black sheep. So we cut it.

I am glad LU is doing the right thing. People, please update to at least Win 7.

Also I would like to comment on this file modification capability. I find it most worrying that there is no security feature that prevents modifying the OS or the game itself.