I'm having the known issue with ..\winsxs causing the system partition to become full.
Several months ago I did the follow fix to apply service pack 1 and this did free up some disk space.
http://support.microsoft.com/kb/2795190
I now have the same disk space issue with ..\winsxs and the KB2795190 fix didn't clean up any disk space. I received "Service Pack Cleanup can't proceed: No service pack backup files were found."
I also found the link below saying the bug has been resolved with Windows 7. I installed desktop experience and attempted to patch cleanmgr.exe, but wasn't able to find a compatible patch for Windows 2008 R2. I did attempt to apply the Windows 7 patch (KB2852386),
but received "The update is not applicable to your computer". Is there a patch for Windows 2008 R2 SP1?
http://support.microsoft.com/kb/2852386/en-us