Look before you Leap - Windows Server 2003 SP1

As with most large Service Pack upgrade installations, it's critical to read, review and test before an install. Read from Microsoft's Support site about which applications Windows Server 2003 SP1 breaks. SP1 for Win2003 is not just a simple "click and go" process but needs a complete and thorough review before installation.

http://support.microsoft.com/Default.aspx?scid=kb;en-us;896367&spid=3198