Microsoft has changed it plans for rolling out XP Service Pack 2 (SP2) to its customers, giving enterprise customers more time to get their plans in place.

The service pack was expected to go out via Microsoft's Automatic Update service on Monday morning US time (6.00pm in the UK) but is now only available for businesses using Windows Software Update Services.

Users of Software Update Services are typically medium-sized enterprises running Windows 2000 and Server 2003, and download new Microsoft updates onto a central server via the web.

The new code can then be distributed it around the corporate network to Windows 2000 and XP machines.

Users with Windows XP Home will be able to access SP2 Wednesday morning US time via Automatic Update, but XP Professional users will not get access until the end of the month.

Microsoft will continue to throttle down all downloads until September, limiting the number of users who can receive the service pack.

"We've had a slight change of plan for end users," said Paul Randle, product marketing manager for SP2.

"We're trying to give enterprise customers more time to get their plans in place. The throttling [of Automatic Update] will still be rolled out as planned, and by the end of the month we will go for full capacity."

Randle added that businesses were being given more time to test the patch against third-party applications.

Last week Microsoft made a software tool available to Software Update Services users to block SP2 from going on to client machines until testing is complete.

The company has also released a list of nearly 50 applications and games that will need to be manually reconfigured once SP2 is installed, including some of its own code. It has committed to updating it regularly and software vendors are also publishing their own guidelines.

SP2 was released to manufacturers on 6 August and will be available in September in shops, on magazine cover mounts or posted direct from Microsoft.