For those who do not know what WinSxS and what issued it has caused, read Aaaron Tiensivu’s (another coworker of mine) blog post here.
In short, WinSxS is a directory which allows you to have distinct versions of the same DLL files. In previous versions of Windows, we all remember the annoying times when we installed a new application only to find it used a shared DLL file that another application needed. The bad part was, that both application used a different version. This could possibly cause the previously installed application to break if you chose to overwrite the DLL file. WinSxS’ existence was to prevent this behavior from occurring in Vista.
The problem here, is systems with smaller C:\ capacity get filled up very fast due to the WinSxS directory taking up a lot of space very fast. Thanks to Matt, we finally have a guide to help free up some of that space on C:\.