About two months ago, Windows Search 4.0 was available as an early preview; today, it becomes officially official as a final version. Folks running Vista will see this update with “recommended” status; likewise, Windows XP users get the “optional” tag. The same features apply from when we last saw this desktop search tool: faster indexing and search returns and cross-OS PC-to-PC searching (like XP to Vista, for example). You can upgrade your Windows Desktop Search by directly downloading the appropriate version at the Microsoft Download Center, where there’s plenty of additional info available as well.One thing I don’t see specifically mentioned that was in the preview: that rollback feature that pulls your last known stable index in case the current one goes kaput. The closest I see to that is this quote: “Improved reliability means that system failures won’t get in the way of the indexer and all of your data will be scanned and available for searches.” I suspect the feature is there, but if it is, it’s not specifically called “Rollback Recovery” like it was prior.