Yes, Vista Service Pack 1 is required, not just recommended, before installing Service Pack 2. This is unusual, if I am not mistaken, in that previous major workstation operating system (i.e. XP) service packs contained all previous service packs or patches.
Also note that this service pack applies to both Windows Server 2008 and Vista. This speaks to the similarities between the 2 architectures, despite their very different roles.
From the Microsoft FAQ on SP 2:
“Why does the SP2 installation require SP1 be installed first?
There are a number of reasons for this, the primary one being the overall size of the standalone package for SP1. Having a cumulative SP2 that includes the updates from SP1 would have made the size too large. Furthermore, because SP2 is a single-servicing model, and since Windows Server already includes SP1, a cumulative SP2 would have meant a needlessly larger file for Server customers. Finally, in the consumer space the majority of customers have already installed SP1 over WU or will be doing so before SP2, so incorporating SP1 into a cumulative SP2 would take unnecessary time and bandwidth.”
SP 2 FAQ Link..
Vista Service Pack 2, which will include all previously included updates, is coming soon. It had been in beta or testing for a while. In other words, the brave (foolhardy?) were able to try it, if desired. This is essentially being a guinea pig for Microsoft, but hey, someone has to do it. Anyway, at this point in time (May 1st, 2009) the official release of SP2 is not available.
“Service Pack 2 (SP2) for Windows Server 2008 and Windows Vista is an upcoming update to Windows Vista and Windows Server 2008. It will provide customer and partner feedback-driven fixes into a single service pack, minimizing deployment and testing complexity. In addition to all previously released updates since SP1, SP2 will support new types of hardware, and will add support for several emerging standards.
As of April 28th, 2009 the Windows Server 2008 SP2 and Windows Vista SP2 Beta program has concluded, thank you for your participation and feedback.
This site will be updated to include Service Pack 2 download details when they are available.” This Technet site has all updates:
Windows Vista Service Pack 1 has been out for quite a while now. If you are using Vista without Service Pack 1, then you should really consider updating! Service Packs are akin to makeovers of the operating system. This is the reason they are so large. They are filled with updates to the code, mostly revolving around fixes and patches for security and stability issues.
Not sure if you have Service Pack 1 (SP 1)? To find out, go to Start menu, aka ‘Start Search’ and type in ‘cmd’, then type ‘ver’. If you have this, then you have Service Pack 1: Microsoft Windows [Version 6.0.6001]. 6001 is a reference to the build number.
Alternatively, go into the system applet within the Control Panel, seen under System and Maintenance. Better yet, go to the Start Search, and type ‘system’ and open the system applet to look for the version. You can also open “System Information”, which will show you the version of Vista as well.
So, in a nutshell, if you only see “Windows Vista”, then you are not on SP 1. Get it at Windows Update or download it here:
Service Pack 1