Sources close to MSFN have told us that the Security Rollup Package for Windows XP SP1 has been delayed due to an unforeseen problem with a specific DLL file relating to DirectX. The Security Rollup Package was originally due yesterday (24th September).
The problem is currently being worked on today and Hardware Quality Labs can take up to 18-48 hours minimum for stability and stress checks. Microsoft is expecting to release the Security Rollup Package sometime after 3pm PST. But in the worst case, it could be re-scheduled for next Wednesday and will undergo another beta testing cycle.
What is a Security Rollup Package? A Security Rollup Package provides a cumulative rollup of security updates that have been offered since the release of Windows XP Service Pack 1 (SP1) in one download, giving users and corporations an easier way to rollout security updates to a number of systems.source