I've read all about WinSXS (Side by Side) and how it tries to solve the DLL Hell problems that have plagued Windows for ages, but I thought it was ridiculous that this folder was taking up over 10 gigs of precious space on my 64 GB solid state drive. A few months back, I replaced my laptop's optical drive with a 500 gig HDD to try to move some of my media and documents over. However, when I went to install the latest service pack to Visual Studio today, I noticed I didn't have enough space to install it. I used a simple tool called TreeSize Free to analyze the disk space and see what was taking up all the room. A quick drill down of the largest item showed that the WinSXS folder was talking up 10.2 GB of space.


Some research showed that if you have Windows Vista SP1 installed, there is a tool called VSP1CLN.exe in the C:\Windows\System32 folder which can be used to clean up the old (pre SP1) files to regain some space. The downside to this is you won't be able to uninstall SP1, so you should make sure the system is running stable with SP1 before running the tool. I looked for this file, but quickly realized that it could not be found! It turns out this was because I don't have Vista SP1 installed (I actually have SP2 installed). If you have SP1 installed, you can use the VSP1CLN file in place of COMPCLN in the directions below.

You can check your Service Pack version by looking at your computer properties: click Start, then right clicking on Computer and clicking Properties. This showed I was running Windows Vista Service Pack 2:


A bit more research later and I found that Vista SP2 has a similar Service Pack Cleanup Tool in the same C:\Windows\System32 directory called COMPCLN.exe. You can start the program by using the following instructions:

  1. Click Start > Run
  2. Type in CMD and press [enter]
  3. At the command prompt, type COMPCLN and press [enter]
  4. Press Y when prompted to continue
    (the application will now start cleaning up the old files)


The size of the WinSXS folder (and potentially others?) should now have been reduced. On my computer, I found that the WinSXS folder was only reduced by 1 GB, but others have seen 3-4 GB reductions.

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  • The AWA

    Well done, Josh. With this tool, some have found a way to save some space on their hard drives.

    They've also made their PCs less reliable. Windows needs the WinSxS folder to keep software running despite requiring different DLLs by the same name.

    The AWA (Anti-Windows Alliance)

  • daniel

    My C drive doees not have a clan up button...and compcln is also not found, did any one done this onb windows 2008 R2?

  • UKNN

    12.7 down to 10.7 - thanks for the tip!

  • Angus

    What a pile of horseshite. Microsoft are wankers.

  • passpartout

    The disk cleanup has resized the winsxs folder, on my windows 7 system, from 12 gb (60000 files, 15000 folders) to 7.7 gb (45000 files, 12000 folders).
    Thank you!!!

  • Joe

    @Thanks for harming others

    If there were good programers in this world, winsxs folder would be unneeded. But on this world is a lot of bad programers. Programers who don't follow standards and they don't know or want to program correctly. This is the real reason for winsxs folder.

    Look at C++ it is over 30 years old and it still has 99% of compatibility. If i compile my 30 years old program with the newest compiler, compiler will without problem compile program and run it.
    Now do the same with dot.net program 1.0 and compile it with 4.0 i dare you! It's just don't work!

    So government should make a law which will ban all programing languages which don't have 99% compatibility with original 1.0 version. So all programing languages as JAVA, C#, and all new age crap should be banned! Those languages are disgrace to all programers all over world!

    Just look at windows you have MFC30 MFC32 MFC40 MFC42,... files but if there would be good programers at Microsoft there would be only MFC file. And this file would be compatible with windows 3.1 and windows 7 programs! Same interface!

    Same problem you can see at JAVA - which is biggest garbage in this world! You program one application in java 1.1 the n java 1.2 comes and application don't work, so you have to reprogram application in java 1.2. Same problems comes with 1.3 version and 1.4 and 1.5 and so on... Is this good programing practice?
    With this folder Microsoft is supporting bad programing practices!
    Programers with bad programing skills should be punished!
    There should be some programing council and programing exam same as there is Medical exam and Medical council. So only licensed people could program.

  • Joel

    Number of files dropped by about 10% (from 55k to 50k). Total space dropped 13.4gb to 11gb.

    Many thanks!

  • Bhellsun

    Thanks a ton.. i freed 6gb of data. Just run disk clean up in windows 7 and select the big junk of files to be deleted.

  • dilum nilanjan

    go to start ----> all pro--->accessories----> right click on cmd ----> run as administrator

    type cleanmgr /sageset:11

    select which you want to remove


    run disk clean up in c drive

    right click on the drive ---> properties---> disk cleanup select types and ok

    to view size of folders

    run treeview or windirstat

  • John Sheffield

    Thank you very much good to have good people giving good advise. I just gained 2 gb more space anther trick that helps me is to compress files to save space in the properties options but be careful not to compress vidios or pictures as they may not return to full size. washerguy

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