If the installer is stuck on the preparation.exe step, you can attempt to bypass it and then repair the installation.
Validates the state of the current installation to prevent corruption during the update. Step-by-Step Preparation for Update 5 visual studio 2012 update 5 preparationexe top
The number one frustration for developers is watching preparation.exe consume CPU for 20 minutes only to fail. Based on Microsoft's archived support documents, the top three triggers are: If the installer is stuck on the preparation
