Reduce The Size Of WinSxS Folder

I was doing a little hard drive cleanup in preparation for dual booting Windows 7 Release Candidate, and of course I was using the trusty (and free) WinDirStat storage visualization tool. I quickly found that the WinSxS folder under C:\Windows was quite massive at 15.3GB. Quite a big chunk out of my 80GB system partition. A quick search around to figure out what it was, and I discovered it's a componentization function of Vista that keeps appropriate versions of system files around for applications that need specific versions. In other words, it really cuts down on "DLL hell." I'd say it does its job quite well, as I have had near zero stability issues with Vista since launch day. But, surely, some of those files are no longer needed? How can you clean them up without causing issues?

With a very good description of what WinSxS actually is, followed by a simple way to clean up at least SOME of the files, check out this TechNet article. They show how to make Service Pack 1 a permanent install, and thereby reduce the need for all of the RTM files you have. You'll also learn why there's not a very good way to clean up the majority of the files in the folder.

I went to Start > Run > VSP1CLN.EXE, then answer Yes, and a couple minutes later it had cleaned up around 3GB of files. Yeah, tiny in regards to today's hard drive sizes, but significant to me in my particular situation with only an 80gb system partition configured. I imagine there will be a similar way to do this again after Vista SP2 comes out.

Now that I better understand this feature and what's going on behind the scenes, I'll be sure to give my Windows partition more storage in the future; knowing that the older my install gets and the more applications I put on it, the larger that folder will get. That's not much of a trade off for increased stability and compatibility I guess.