When the SP1 beta for Windows 7 and Windows Server 2008 R2 was released a couple of months ago I pushed it in onto my Windows 7 machines without blinking. I was also about to install it (using the Windows Update script) on my Windows Server 2008 R2 Hyper-V server but thought twice as I cannot live without my virtual machines and I use many of them in my daily work.
Anyway I was kind of suprised the other day when I rebooted the Hyper-V server only to learn that the service pack was installing. Aaargghhh! I do not blame Microsoft, I blame my own stupidity. But hey, everything worked fine afterwards and by reading the release notes I can sleep good at night knowing there won’t be any problems when the next SP1 release comes.
Once you have installed this service pack, you will have to uninstall it prior to installing a later release of this service pack. The settings of any virtual machines will remain intact during the uninstallation and installation, but virtual machines that have RemoteFX or Dynamic Memory enabled will not appear in Hyper-V Manager while the service pack is removed. In addition, any snapshots taken when RemoteFX of Dynamic Memory was enabled will not appear in Hyper-V Manager. They will reappear and functional normally once the later release of SP1 is installed.
Lesson learned; check!