Microsoft has released a blocking tool for businesses that will prevent an automatic download of the first service pack for Windows Server 2003.

A similar blocking tool was produced for Windows XP SP2 to let companies test their systems before introducing the wide-ranging update.

The new Server 2003 blocking tool works with a registry key, a script or a group policy setting in Active Directory, will prevent SP1 through Microsoft's online patch download services, Automatic Update, Windows Update or the newly launched Microsoft Update.

Most businesses do not have automatic updates installed on desktops and certainly not their servers but during the XP SP2 saga, even Microsoft was surprised how many corporate users had activated Automatic Updates on their corporate desktops, so it has created the blocking tool to avoid annoying customers.

"There are more people than you would expect with [auto updates] turned on at the server," says Samm DiStasio, director of product management for the Windows Server division. "We are just trying to make sure the tool is available well in advance of us turning on automatic updates. But let's be clear, this is a tool for blocking automatic updates. You can still install SP1 on their servers if you have the disk or you want to download the bits on your own."

Windows Server 2003 SP1 was officially released on 30 March, but its availability over the Web is planned for 26 July. The blocking tool will prevent the update's download until 30 March 2006. It comprises a Microsoft signed executable, a script and an ADM template.

The executable creates a registry key with a switch that will block or unblock the download of the service pack while allowing all other patches and fixes to be downloaded. The script will do the same thing as the registry key, but Microsoft says it allows users to specify a block or unblock on a specific machine name.

The third option is the ADM template, which works with Active Directory's group policy technology. The template includes new group policy settings to block or unblock delivery of the service pack.

Microsoft also noted that Windows Server 2003 SP1 requires users to accept and initiate its installation so even if the service pack is automatically downloaded it must be explicitly accepted and installed by a server administrator.