Recently, while investigating an issue related to a .NET Framework hotfix installation problem, I reviewed the contents of the System Update Readiness Tool knowledge base article. I noticed that the contents have been updated since the release of Windows 8. Instead of needing to download and run a separate tool, the diagnostic and repair functionality in the System Update Readiness Tool is now built into Windows in Windows 8 and Windows Server 2012. This change should make it much easier to investigate and fix issues on Windows 8 and Windows Server 2012 such as the one I described a while ago in this blog post.
You can find more detailed information about how to use System Update Readiness Tool functionality in Windows 8 and Windows Server 2012 in this blog post from the Windows servicing team.