My colleague Mary Jo Foley has the details on some compatibility problems being caused by the Windows 2000 "Update Rollup" that Microsoft shipped last month-end.
There's a Microsoft KB article explaining the bugs that are affecting products from Sophos, Panda, Internet Security Systems (ISS) and Citrix.
From the story, it appears that the infamous MS05-019 security bulletin, first released in April and re-released in June because it was breaking some applications, is causing more problems again.
Also of note, the blocking tool to delay the automatic download of Windows Server 2003 SP1 will only be available for a few more days. If you need it, hurry and get it.