Into Windows Vista, the WinSxS folder was able to be cleaned up with a third party tool, called “WinSxS Lite” Only for Microsoft Windows Vista. In the initial release of Windows 7, we lost that capability. But it has since returned with MS Windows Se7en Service Pack 1.
In previous versions of Windows, such as XP there was a component called ‘Windows File Protection’ which was used to make sure that all of the many system files were protected and backed up. These files were backed up in the %systemroot%System32dllcache folder. If you had a problem and lost a system file or one of these files had been corrupted, you could run the ‘sfc /scannow’ command and the files would be replaced with the backed up copy in the dllcache folder. The dllcache folder was typically 500MB or larger.
In Windows Vista and Se7en, ‘Windows File Protection’ has been replaced with ‘Windows Resource Protection’ which, essentially performs the same function. The ‘dllcache’ folder no longer exists in Vista & Se7en, it has been replaced with the %systemroot%WinsxsBackup folder.
This folder is NOT ‘a backup of a backup’, it exists only to make sure that files required for Vista/Se7en to boot and operate are protected.
The WinSxS folder is used to store install and uninstall files, windows packages (current and previous versions of a component) and out-of-band releases. You should not completely delete this folder. Post Windows 7 SP1, there is now a way to remove the unnecessary files from this folder using the command line (elevated/admin mode -> Click Start -> Type “cmd” in Search. Right click on “cmd” and choose “Run as Administrator”). This is great for reducing the Windows folder size for SSDs and netbooks. In my case it saved 3.5GB of space.
Copy This Command
dism /online /cleanup-image /spsuperseded
Right Click in CMD Screen and Click Paste and press Enter Button.