There have been a couple of reports of problems  regarding the new UpdateRollup 1 package for Windows 2000. One user on the Patch Management mailing list said he's having problems with printing after installing the update. His system prints much slower now. Another person said he experienced 100% CPU utlization on two Citrix Metaframe servers after installing the update. He removed the update, rebooted the servers, and the problem went away. 

Have you experienced any problems with Update Rollup 1?

Update September 13, 2005: Microsoft re-released Update Rollup 1 for Windows 2000 SP4.