Why is the Windowswinsxs directory so large?

I wanted to put some sort of content on here quickly, so here is a link to my teams blog which I wrote last year about a common question asked when it comes to servicing the operating system.  "Why is the \Windows\winsxs directory so large?"  The short answer is that it is really a "flat" of your Windows installation which means that its all of the files needed for you to use Windows without the need to put a CD\DVD into the drive every time that you need to add a new feature or update a file.

For more information on why its the size it is, see my old post here:


 Also, check out some of the other cool information my team has regarding topics like clustering and DPM.

Comments (8)
  1. Sorry, didnt see these comments until now.

    As for "removing unused junk", you cant.  The winsxs directory is there to service all of the features of the OS, including upgrades.  As patches are applied, it will grow, but if its more than 7-8GB, then you might have something else going on because I have seen very few instances of directories larger than that.

    In regards to extending the boot volume, if you have drive space available on the same contiguous physical drive, you can extend it.  You cannot extend drives across physical boundaries.

  2. If your Winsxs directory is only 9GB then you're seeing growth from another place.  What do you mean that there might be as much as 12GB lost during the day?  Do you know what directory you're accumulating the most space in?  That might help narrow it down.

  3. Fixed..sorry, I get bad about tags.

  4. Pronichkin says:

    BTW, why doesn't this post have WinSxS tag? (blogs.technet.com/…/winsxs).

  5. Rob Greene says:

    Instead of "Why is the Windowswinsxs directory so large?"  I want to know "how do I remove unused junk int there?"   I have 2.5 Gigs free space left on my boot drive (30 gigs before installing Windows 7).  

    I want to boot drive as small as possible so I can back it up.   I do not use the My Documents or whatever it’s called these days.  

    I dont care why winsxs is there, how do I remove the unused parts?  If not, how do I remove all of the junk.  I would like to know why System32 not enough for you?  But you will have to tell me quickly before I run out of boot drive space and my windows crashes and dies.

  6. Rob Greene says:

    for that matter, why cant I ‘extent’ drive C from Disk Manager.  My 500 gig drive has 45 gigs unused.  All of the other partitions can be ‘extended’ or ‘shrink’ but the important almost fool boot drive is unchangable.  rwgreene999 at hotmail.com

  7. David says:

    So someone, anyone, is suggesting that I have had 21, 000 installs on my system? Or 21,000 builds? Or has 21,000 patches been applied to my system? In less than a year? Or that my system should or could manage that number of system config sets of any flavor?

    and NOT suffer a performance hit?

    Or is it that MS just can’t figure out how to manage this that is clearly just an expedient answer to a dilemma at the cost of the end-user?

    Mine is now over 7G – on this install. Was larger before that last crash and re-install.

    And my C: drive is getting crowded.

    I foolishly only allowed 90G for OS and mainline apps only.

    There must be a way to identify redundant files and directories. And waste.

    I have not run many tasks in as many as 5 different languages, which appear to be the only difference (title bar) of the content of many, many folders.

  8. Dearnaley says:

    I run SBS2008 for a small office (only 3 computers) and the server keeps filling up overnight which stops our emails. There can be as much as 12GB lost during a day when there is very little activity on the client computers. I'm not IT  trained and I'm spending all my time reading blogs to find yet another fix to reduce the overcrowding, which all work temporarily but then we go right back to square one.

    Our winsxs is currently 9.19 GB: what did you mean "there might be something else going on?

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