A second version of the Service Pack 1 Release Candidate (RC) has been made available publicly. Microsoft had indicated that the 'Refresh' version of the nearly-finished (hence RC) Windows Vista update would not be made available for public download.
The release is now available via Windows Update and has been made so "in the interest of gaining additional tester feedback" according to a statement released by Microsoft. As with the original SP1 RC you need to install a script to enable Windows Update to refresh your system - this is available publicly from Microsoft Downloads.
If you've already installed the original SP1 RC, you'll need to uninstall that to get the Refresh version (build 17128). However, the refresh doesn't offer a great deal, instead fixing some minor problems people had installing SP1 RC in the first place.
In a TechNet post signed from John Gray and the Vista SP1 team, those behind the RC Refresh say there will be more to follow. "We have another small batch of install failures that were not fixed yet in this build, but will have a fix prior to RTM. We know that there will still be some install issues with this build but it is a lot better.
"We've been hard at work on fixing the issues."
Some users had problems installing the original RC, but we've already read about some others - not least at the TechNet forums - experiencing problems installing the Refresh when they had no problems with the original RC.
As with the original SP1 RC release, you will need to have some existing Windows Vista updates installed on your system - check the Downloads page for details.