A compatibility issue has forced Microsoft to delay the release of new service packs for Windows Vista and XP.

Windows Vista SP1 and XP SP3 have been pulled from the Windows Update utility and the Microsoft Download Center until a fix can be issued.

A company spokesperson told vnunet.com that the delay is down to a compatibility issue with Microsoft's Dynamics RMS software, which is used by small and medium-sized retailers to manage their business.

The spokesperson declined to comment on when the service packs would be released again.

Microsoft is in the process of implementing a filter which will prevent Dynamics RMS users from downloading the service packs while allowing all other users to update their PCs. The company is also testing a fix for the issue.

News of the delay comes on the day that Microsoft had planned to release the XP service pack, and just eight days after Microsoft sent the first versions of the service pack to manufacturers. It also comes just five days after Vista SP1 was released.

Microsoft has advised all Dynamics RMS users running either of the service pack updates to contact its Customer Support Services for more information.