Tuesday was supposed to be the coming out party for Windows XP Service Pack 3, but alas, it was not to be. Microsoft delayed the Web release of the software after finding a compatibility issue.

In the last few days, Microsoft found a compatibility problem between Microsoft Dynamics Retail Management System, an electronic checkout system for small- and mid-sized retailers, and both Windows XP SP3 and Vista SP1.

Though that issue would affect a relatively small number of customers, and though many point-of-sale systems use Windows XP Embedded rather than the full version, the company has delayed releasing Windows XP SP3 at all via Windows Update or Microsoft Download Center until a filter is in place to prevent customers who have the Retail Management System from downloading the service pack. It's unclear how long it will take for Microsoft to institute a fix.

Though this delay will likely be short, it's the latest in a series of postponements to Windows XP SP3, which was delayed in early 2006 until 2007 and then again until this year.

According to a post on Microsoft's Windows XP SP3 forum by Chris Keroack, release manager for Windows serviceability, the delay is in place to "make sure customers have the best possible experience."

Though Windows XP SP3 isn't available for automatic download via Windows Update, the files remain available on the Windows Update servers for download for those willing to look. The update has already been released to manufacturers.

Windows XP SP3 is a roll-up of all of the updates to Windows XP since SP2 was released four years ago and includes a number of other new features. For example, network access protection -- which is included as part of Windows Vista -- can make sure systems are patched before they can access a network. Several of the other new features are also security-oriented.