On Tuesday, Microsoft began notifying customers that it has established new deadlines regarding how long they will be able to block Windows XP Service Pack 2 (SP2) from downloading automatically to their systems.

Microsoft made available to customers in August a couple of different tools to temporarily disable the delivery of SP2 to users machines via its Windows Update/Automatic Update patching services. A number of customers had requested these tools, claiming they were not ready to take delivery of SP2, as they had not tested SP2 adequately to make sure it did not break their applications.

Originally, the tools were set to postpone delivery via Windows Update/Automatic Update for 120 days, starting August 16. But on September 7, Microsoft extended this deadline to 240 days, or eight months, from August 16. As a result, Microsoft will now begin pushing SP2 to all Windows XP and Windows XP Service Pack 1 customers automatically via Windows Update and Automatic Update as of April 12, 2005.

Microsoft noted the change in its patch-blocking dates on its TechNet IT portal Web site, as well as in a note it sent to corporate customers via e-mail.

Microsoft released SP2 to manufacturing on August 6 and has been rolling it out in stages to its various XP customer bases over the past month.

Even though Microsoft has deemed SP2 a "critical" update, some corporate and home users have been leery to install it. Microsoft has acknowledged that a number of applications, including several of its own, do not work properly with SP2 unless certain settings are changed. And a number of third-party hardware and software vendors still have yet to provide patches and updates to their products that will allow them to work with SP2.

Microsoft has said there are an estimated 300 million XP users. This fall, Microsoft will be reaching out to this user base via its "Protect Your PC" campaign, in an attempt to make sure as many XP users as possible install the SP2 update.