Hello AskPerf readers. My name is Scott McArthur and I am a Support Escalation Engineer with the Setup & Cluster team. I know you�re probably thinking that one of us has somehow found our way to the wrong blog! I recently ran into an interesting scenario while working on a customer issue, and since this has some impact on Application Compatibility, I figured AskPerf would be the best place to write about it.

The customer�s issue I was working on dealt with an application install failure on a 64-bit installation of Windows Vista. The application in question required Windows Vista Service Pack 1 as a prerequisite for installation, and the system administrator duly installed SP1 and then proceeded to launch the installation of the application. And then, a funny thing happened � the application returned an error, indicating that Service Pack 1 for Windows Vista was not installed. According to the Windows Update logs, the SP1 installation appeared to have completed without incident. Trying the installation of the application on another machine, the administrator found that he encountered the same problem on every Windows Vista SP1 machine. As Alice said, while in Wonderland, �curiouser and curiouser� �