Solved WinSXS Folder not actually consuming lots of space

I've seen a recurring post on many forums discussing the absurd amount of disk space being consumed by the C:\Windows\WinSXS folder.

I've done some testing in house to confirm the fact that the files in this folder are predominantly hard links to a small number of files and it's not really taking up anywhere near the space that Windows Explorer is reporting.

Here is a link to better explain what I am talking about:
WinSxS Disk Space Usage: It’s Not What You Think (David's Blog)


Here was my conclusive test:

1). I took a virtual machine and created a new 200MB hard drive that I assigned the drive letter E:

2). I created a subfolder on E: called WinSXS. So, I had E:\WinSXS

3). I copied in a 13MB zip file into E:\WinSXS.

4). I then created 20 hard links to that zip file with the command shown in the link above (mklink /h hardlink#.zip original file

5). According to Windows Explorer, E:\WinSXS is now 267MB in size.....even though the entire E drive is only 200MB.

6). From a cmd prompt, running dir on E:\ shows 174,543,872 bytes free.

Therefore, tools like Windows explorer and TreeSizePro will report that that WinSXS folder is consuming massive amounts of space....while the true fact is that the folder is being misrepresented because the reporting tools do not understand the difference between hardlinks and real files.

Sorry for dragging up this old post, but it answers a question I've been searching and searching for an answer to. I can confirm that on my system, when I add up all the root directories on my main hard drive then subtract the "size" of the WinSXS folder, I get the reported used space in the properties of my boot drive.

Thanks pparks from ending this tail chasing!

LafinJack said:

Thanks pparks from ending this tail chasing!

Click to expand...

Your welcome. After 10,000 views and not a single reply, I was wondering what was going on.

DalekOverSeer said:

yes winsxs my not actually using that amount of space, but the space is still reserved by windows none the less. the only way to free up that space for use is to use the one procedure to move the winsxs folder to another drive. the procedure is in no way for novice. i strongly recommend against doing it.

Click to expand...

No, it is not used by Windows and reserved. You assume the space is used as right clicking on the folder and selecting properties says that it's X amount in size. But as I've shown above, if the folder "REALLY" had 270MB of stuff in it, then the 200MB hard drive would have been filled beyond capacity.

So, when I put in the 13MB file, Windows explorer showed that my D drive went from 200MB free to 187MB free. Once I created the 20 hardlinks, Windows explorer continued to show that my D drive had 187MB free. A command prompt showed 187MB free. But if you were to look at D:\winsxs with Explorer, windirstat or treesize free....it would "claim" that the folder was 270MB in size.

Edit: I am researching ctts.exe and it's ability to properly distinguish between hardlinks and real files. From initial observations, it appears that C:\windows\winsxs might be more real files and less hardlinks than originally expected. This would obviously impact my statements above.

Here was the guide used as reference at first;
Disk Space - Engineering Windows 7 - Site Home - MSDN Blogs

In this guide, it says this;

In practice, nearly every file in the WinSxS directory is a “hard link” to the physical files elsewhere on the system—meaning that the files are not actually in this directory. For instance in the WinSxS there might be a file called advapi32.dll that takes up >700K however what’s being reported is a hard link to the actual file that lives in the Windows\System32, and it will be counted twice (or more) when simply looking at the individual directories from Windows Explorer.

Click to expand...

However, when you run something like ctts.exe...it seems to indicate that an overwhelming majority are "real" files and not hardlinks. In my case, out of nearly 6GB reported (somewhat erroneously by Windows Explorer), ctts.exe says that only 78MB are hardlinks. Well, that wouldn't jive with the MSDN blog article from above.

pparks1 said:

Hmmm...might have to revist this topic under Windows 7 to see if there are not as many hardlinks as MS led people to believe. If there are legit files in C:\windows\winsxs..they would take space. But my understanding was that these files were Mostly (80%+) hardlinks. However, ctts.exe seems to say otherwise...as it shows my 5.8GB of C:\windows\winsxs consists of only 75MB of hard links and 5.7GB of actual files. Most everything I have read in the past was reverse of this in Technet...meaning 75MB of files with over 5GB of hard links.

Click to expand...

the prob with microsour is they really do not have a clue. i say this because it was microsoft that told me that for the most part that winsxs contains psychical files. they got lucky when they created win 7.

Alright, figured something out. Thanks to this thread ( Windows 7 Free Space - Neowin Forums - Page 2).

You have to run ctts.exe against C:\windows and not just C:\windows\winsxs.

The output for me against C:\windows says
13.2GB of total size in use. And TreeSize agrees that C:\windows is indeed 13.2GB. (We agree both will count hard links and inflate real number)
4.2GB of space is consumed by Hard Links
9.0GB of space is actually used by "real" files. ( I believe this is value of ctts.exe..."real files" here consume about 9.0GB of space.

But TreeSize Free, and Windows Explorer both say that my C:\windows\winsxs folder is 5.8GB in size.

Therefore, the conclusion would be that out of 5.8GB reported, nearly 4.2GB is coming from other areas within the the C:\windows directory. Thus, approx 75% of the space is represented by hard links.

So, I would maintain that if I flat out deleted C:\winSXS that I wouldn't get back 5.8GB of free space, but instead would get back (5.8 - 4.2) 1.6GB of space.

So, if you had a 20GB hard drive...even with the "appearance" of a 13.2GB C:\windows folder, I think actually 9.0GB of space is used, and you would really have yourself about 11GB free if you went to a command prompt and typed DIR. I think you could put about 11GB of more files onto that 20GB drive before it would truly be full. Even though, it would seem that counting up the Windows folder with Windows Explorer means that 13.2GB is used and thus only 20-13.2 = 6.8GB would really exist.

And that's what I showed with my example at the top. I could make it "appear" that D:\winsxs was almost 270MB in size..even though my hard drive itself was only 200MB. All of the tools said D:\winsxs was taking 270MB....but yet I could still copy about 187MB of more stuff onto the drive before it really was full.

Everything sound logically till I tried to copy a file which according to the info should can be fit in there. But all I get was this >



So should I trust in first post explanation and search the error in my system or what?

Alright, I'm not sure why this topic is so hard for people to wrap their heads around, but let me try a different approach.

I'm going to start out with my own personal laptop. Here is what my C drive looks like as I start my exercise. My 80GB Intel SSD has about 44GB free space.


Here is what TreeSize Free shows, and the relative size of my WinSXS folder;


And finally a command line view of how much hard drive space I have;


So, I'm going to create a new folder. It's called C:\windows\ATestFolder and it contains a 569MB .PST file


And sure enough, looking at a command line shows that my C drive has about 569MB less space available.


So, everybody with me thus far. I have a folder, with 1 real 569MB file. This reduced my hard drive by 569MB. No shocks whatsoever.


Ok, so now lets go in and create 6 hard links to this same file; Notice how the folder now has over 4GB of stuff, my free size really hasn't really dropped.


So, later I run TreeSize Free and now try to figure out why my hard drive is so full and I find C:\Windows\ATestFolder is sucking up a whopping 4GB of disk space. (but take a quick look at the Free space at the bottom and compare to the free space in the Treesize Free image above...it's about 569MB different...and that's because of my 1 real file. But it didn't drop my usable hard drive space by 4GB like the folder would "seem" to indicate)


So, I'm going to simply delete everything in C:\windows\ATestFolder and get my 4GB of free space back. But notice what happens as I delete the files in the folder



So, as you can hopefully see and understand...even though Windows explorer and TreeSizeFree seems to indicate that I have a whopping 4GB folder called C:\windows\ATestFolder...if my hard drive were ACTUALLY full...deleting this folder would NOT get me 4GB of free space back... I would have gotten back 569MB of free space back as I had 1 real file and 6 symlinks. So, while it appeared to suck up nearly 4GB of data to most tools.....if you look at my command prompts and the bottoms of my TreeSizeFree printouts that even with the addition of this whopping 4GB folder, my actual disk space didn't go down.

If you hard drive is full, it's stuff in places other than directly in C:\windows\winSXS. Most of the stuff in here, probably 60% or more are simply hard links..and are misrepresented in most tools. Deleting that folder would not get you back the amount of disk space that the folder seems to consume.


GET IT?

Fine explanation, but repeat things that are already up in the thread. You see, I`m not some maniac wanting to shrink his windows for the sport.
I just happen to see this info and got me thrilled if its really like that.
So, I don`t care to delete files but for possible real use of these masked megabytes. In other words following your very explanation in first post I should be able to copy that file which was only 600mb over declared from windows explorer free space. Which itself should be much larger because of these false files /just hardlinks/
Lets do the math. Here are all my files without folder windows
10.9Gb + 9,87Gb /files from windows which aren`t hardlinks/ = 20,77GB
My "C" is 29,9GB - 20,77Gb = 9,13Gb which should be real for use. And I tried to copy a file - 8.2GB - if you are right it should can be done. But as you can see from my screenshot in my ргevious post - its not possible.

So, whats now?

THE ONLY THING THAT MATTERS
Right click on the file in question and see how many bytes it is.
Then, go to a command prompt and run, dir. See how many bytes free you have.

If you have enough bytes free, you can copy the file. If you don't, you won't be able to copy the file. No amount of hard links will change the above.


MORE DISCUSSION
The amount of "actual" free space is shown properly with Windows Explorer and with the command prompt. However, if you go on a witchhunt looking for where space is consumed, you run into this C:\windows\winsxs folder, windows explorer and TreeSize free will show it being XX in size...but that may or may not be true. This is where most people make the mistake. They run out of space, and want to free stuff up and are appauled that C:\windows\winsxs looks to be huge.

You are reading into this, assuming that since these are hardlinked files...you should have this "extra" amount of disk space on top of what Windows explorer and what the command prompt says. But these tools are taking them into account when it shows you free space...they just aren't able to show you how much "true" space they are really consuming when you look directly at the properties of C:\windows\winsxs.

And in your screenshots above, you were only short by 500MB or so...so very very close. It could simply be some rounding mistakes, or considering 1MB to be 1,000,000 bytes versus 1,048,576 bytes.

Lets make it simple. So that space exist but is not usable in normal everyday way. That I wanted to know

Belgarionbg said:

Lets make it simple. So that space exist but is not usable in normal everyday way. That I wanted to know

Click to expand...

You aren't making it simple, you are not understanding it completely.

1). Some of the files, are real files. They really take up some space on your hard drive. These reduce the amount of space available to store files and install applications.
2). The other items are hardlinks to files that exist someplace else on the hard drive. Now, the real true physical file exists and WILL decrease the amount of space that is really on your hard drive. The hardlinks are NOT real physical files and DO NOT consume disk space on your hard drive.

Go back to my example recently.

• I started with 44.9GB of free disk space.
• I copied in a "REAL" file that was about 650MB in size
• My hard drive space dropped to 44.2GB of free disk space. This is what applications have access to and represents how much stuff I can copy onto my hard drive before it's full.
• I then created numerous hardlinks and made it appear that my C:\Windows\aTestFolder had almost 4GB of stuff in it.
• I demonstrated that TreeSize free would report an increased size of my C:\windows folder and would report that C:\windows\aTestFolder was 4GB in size.
• But looking at my command prompt showed that my free drive space stayed consistent at 44.2GB of free space. it's the same amount of space that I had above, applications still have access to the exact same amount of free space. (even though I magically created what appears to be 4GB folder called C:\windows\aTestFolder)
• I could have made 500 hard links to that same file and made it appears that my C:\windows\aTestFolder was (500 x 650MB) was 325GB in size. Treesize free would show a 325GB folder, and Explorer would show a 325GB folder if I looked at properties. All miraculously on my 80GB hard drive.
• Even with 500 hard links to the file, my command prompt would continue to show 44.2GB of space free. (Because none of these hardlinks actually decrease the amount of free space on your hard drive.

So, NO....it's not like the space exists and you cannot use it in everyday use. The space that is free can be demonstrated with a command prompt or looking at Windows Explorer...or the bottom of the TreeSizeFree window. The hardlinks DO NOT, and HAVE NOT reduced the amount of free space on your hard drive. The amount of hardlinks have never counted against you.

the 4.2GB worth of hardlinks you discovered have NOT reduced your available free space by 4.2GB. In fact, if they did actually count against you, instead of having 8GB of free space on your hard drive, it would actually drop to 4.

YOU ARE NOT BEING CHEATED OUT OF ANY SPACE, THE SPACE ISN'T MASKED OFF AND UNUSABLE.

It appears Windows (Vista in my case but I suspect 7 is similar) makes some use of hard links but not as much as it might.

In my case, sizes for complete c:\Windows reported by CTTS or WinDirStat are 20GB; with CTTS reporting hard links saving 2.65GB; to give a real 17.4GB.

Using Duplicate Cleaner (Duplicate Cleaner - Reviews and free Duplicate Cleaner downloads at CNET Download.com) indicates that there is a further 1.8GB that could be saved by extra hard links.

I have not yet bitten the bullet and done the hard linking. It might well not be safe; depending how Windows went about later updates it could implicitly change something in winsxs without realizing; whereas once something is in winsxs it should be immutable.

This is all very nice, but Windows7 keeps reporting to me (popup from systray) "you are running out of disk space"...

... any clues about how to tell _it_ that I'm "not really"?

Thanks!

GaJ

GreenAsJade said:

This is all very nice, but Windows7 keeps reporting to me (popup from systray) "you are running out of disk space"...

... any clues about how to tell _it_ that I'm "not really"?

Thanks!

GaJ

Click to expand...

Ugh..if you are getting prompted that you are running out of space...You ARE running out of space. Whatever you see "free" from a command prompt or from My Computer is what you have free.

I don't really think the problem is your explanation of hard links. Obviously there are more real files in winsxs than hard links. Remember, Windows is reporting real space. And we are finding the winsxs to be quite large, and we need to know what can be done to alleviate real disk usage in the winsxs folder since it seems to be pretty redundant.

Honestly, I don't want windows to "archive" ANY manifests, assemblies, libs, or have restore points.. all I do is play 2 or 3 games on it, and that's it. If something happens, it's easier to re-install. Still, I think we would all like to keep our systems clean and trim.

i had this problem today and thought i'd help out with an explanation, some of these are way too complicated haha



first to find out how much windows adds the files up to. go in C: drive and select everything (make sure you've unhid all files if you don't run with this normally) right click > properties:
116gb (124,992mb) total

then to find out the true overall usage on the drive, unselect all files and right click in C: > properties (or do it in my computer whatever floats your boat)
111gb (119,672mb) used

so if file properties is reporting 124,992mb but drive properties says only 119,672mb being used then of (in my case) winsxs' 7102mb reported in properties, 5320mb is hardlinks

well, that is assuming winsxs is the only place with these hardlinks, but i assume so