Where's All My Disk Space Going In Vista?

I've seen many questions, and even more incorrect or incomplete replies about missing disk space in Vista. You got a 160GB hard drive and you've only installed a few programs, but you're missing a LOT of disk space! Where did it go? There are numerous possible reasons why your disk is getting used up -- sometimes it's being used by useful services, and other times it's just being wasted.

So where does the space go?

  • Volume Shadow Copy: This is biggest reason for "missing" space in Vista! Instead of explaining it myself, I'll quote wikipedia:

    Shadow Copy (also called Volume Snapshot Service or VSS) is a feature in recent versions of Microsoft Windows that allows taking manual or automatic backup copies or snapshots of a file or folder on a specific volume at a specific point in time. It is used by NTBackup and the Volume Shadow Copy service to backup files. In Windows Vista, it is used by Windows Vista's backup utility, System Restore and the Previous Versions feature.

    This service can be very useful, and is a good idea to keep it enabled. However, it does eat disk space. A LOT of disk space. By default it allocates %15 of the disk to store it's data. On a 160GB disk, that's 24GB! A lot of people have been noticing that after a few weeks of using their new system, free space seems to shrink daily. This is because the space is not allocated right away, only when it's needed. It will stop when it reaches %15. At that point, it will delete older versions to make room for newer ones. For all the details about Shadow Copy, read this article at ZDNet for a really good explanation.


  • Marketing Many people notice missing space right when they open the box. They bought a system with a 160GB hard drive, but Windows shows the total drive capacity as 149GB. That's a difference of 11GB right off the bat. The reason for this has to do with how you measure capacity to begin with. We measure bytes using progressively larger sizes, starting with K (kilobytes), M (megabytes), G (gigabytes), each one standing for a multiple of 1000. So 1K = 1,000, 1M = 1,000,000 (1000 * 1000), and 1G = 1,000,000,000 (1000 * 1000 * 1000). These are the units that companies use when they advertise the size of their disks, so your 160GB drive is 160,000,000,000 bytes in these measurements.

    However, computers are binary systems, and measuring in multiples of 1000 isn't the way they do things. The closest thing we have in binary is 1024. So, for a computer, 1K = 1,024, 1M = 1,048,576 (1024 * 1024), and 1G = 1,073,741,824 (1024 * 1024 * 1024). As a result of this, a computer thinks that 1GB is bigger than what a person typically refers to as 1GB (a difference of 73,741,824 bytes). If we take our example of a disk that's advertised as 160GB, and divide by what a computer thinks is 1GB, we wind up with: 160,000,000,000 / 1,073,741,824 = 149.012, which is what Windows says is the drive capacity.

    This measurement makes it seem like the drive is smaller, which is the reason I call this "marketing". Everyone wants to make their drives seem bigger, so they use the larger number, even if it's not exactly accurate.

    Because of this confusion, new standards of measurement have been devised to help clear this up. Officially, the term "megabyte" refers to 1,000,000 bytes (1000 * 1000), and the term "mebibyte" refers to 1,048,576 bytes (1024 * 1024). The abbreviation for "megabyte" is "MB", like you're used to, and for a "mebibyte" it's "MiB". Notice the "i" in there. It's subtle, but important to make the distinction. You probably won't see these units in use by large companies for a while, but it's something you should be aware of anyway. See mebibyte for more information.

    Here's a table comparing the "marketing" size vs. the computer size for some typical drive sizes:

    Typical drive sizes
    Marketing Computer
    80 GB 74.51 GiB
    100 GB 93.13 GiB
    120 GB 111.76 GiB
    140 GB 130.39 GiB
    160 GB 149.01 GiB
    200 GB 186.26 GiB
    250 GB 232.83 GiB
    300 GB 279.39 GiB
    320 GB 298.02 GiB
    350 GB 325.96 GiB
    400 GB 372.53 GiB


  • Essential System Files Another thing that can use up a lot of disk space are some essential system files, specifically, the pagefile and the hibernation file. The pagefile is part of the virtual memory system, and is required by the system to function correctly. It can take up to a few gibibytes of space, 1GiB - 4GiB, depending on how much RAM you have in the system. The other file, "hiberfil.sys", is used to save the state of your system when you hibernate it. This file is about as large as the amount of RAM you have, and is required for hibernation to work. If you disable hibernation, this space should get freed-up, but then you won't be able to hibernate.
  • Temporary/Working Files Here's another place that space gets eaten quickly. I recently cleared out my temp folder, and found almost 1GiB of data in there. Since this stuff really is "temporary" data, it's pretty safe to delete. A lot of this comes from installer programs -- when you install new stuff it decompresses data into the temp space. Other files that fall into this category are things like temporary internet files, the index for disk searching, thumbnail cache for thumbnails that show up when you view a folder of pictures or videos, etc... Usually you can use the "Disk Cleanup" wizard to clean this stuff out. If you clean it out, it's probably a good idea to reboot.
  • C:\Windows Then, of course, there's Vista itself. Vista can take 6GiB or more on the system. That's not terribly huge, but it is there. Of course, it's sort of required for your system to run, so there's not much you can do about it :)
  • Recovery Partition Many, if not most new systems these days come with a "recovery partition" on the disk. This partition often contains all of the software necessary to restore your system to the factory default state. They put it there so if you have serious problems with your software, you can, as a last resort, recover from it. However, this process will delete all of your data.

    The partition can be anywhere from about 5-10GiB, but it can vary. There are ways to get rid of it and reclaim that space, but never do so unless you have burned the "recovery discs" onto some DVDs first. The process to make recovery discs should be detailed in the documentation of your system. Once that is done, you can delete the partition, then expand your C: partition to use that space.

  • Copies of Installation Media Chances are if you copied some DVDs to your hard disk yourself, you know about it. But there's another way this can happen. Your OEM may have copied the entire contents of the Vista Installation disc to your hard drive. This is useful if you want to perform an Anytime Upgrade because Vista will need those files to perform the upgrade. However, that's going to take up a few GiB of space on your disk. If you can find this folder, sometimes called "WAU", you can safely burn this to a DVD and then delete the folder. Even better would be to make a bootable disc that you can use. You can use vLite (freeware) to burn this type of disc.

    Another program that does this is Microsoft Office. When you install Office, it copies the entire contents of the disc onto your hard drive. Unfortunately you cannot remove it, as these files are needed when you do an Office update.

One way you can track down what's taking a lot of space is by using an open source tool like windirstat. Don't go deleting stuff you don't know what it is! Many are the stories of people who reorganized "this c:\windows thing" and for some reason their systems didn't boot anymore!

One principle to keep in mind is that free space can be considered wasted space. If you don't need that space now, let Windows use it for temp files, indexing databases, volume shadow copy, etc... so you can get the benefit of those services. Only when you need that space should you worry about deleting those things.

Thanks for compiling this data on Vista. This is why I currently avoid Microsoft's flagship OS like the Bubonic plague.....15% of the hard drive space dedicated to Shadow Copy? No thankyou to that bloatware. That's why I prefer a Linux operating system. Open source is so much more streamlined and you are less susceptible to viruses and trojans that prey on Windows users.

Thanks for your input, but on Linux you will have many of the same issues. Running Linux does not change how marketing people measure the disk size, and you still lose space in the swap file/partition, temp files, and system files, and many distros cache packages on the local disk. A recovery partition is not a result of Vista but a result of the company that installed the system.

The only thing you can blame on Vista that you don't have in Linux is the Volume Shadow Copy, which is making better use of your disk space than if you had it all empty. Shadow Copy with Previous Versions is quite a nice feature, and it would be nice to see this type of innovation on the Linux side of things.

And no, "I keep backups" is not a valid response. Shadow Copy is like having all of your data files in CVS or SVN, and the system automatically checks them in/out every time you make a change. But it doesn't require user intervention.

The current fashion is to bash on Vista, which people also did when XP came out (but the Internet was not as prevalent then, so the echo chamber didn't reach such hysteria). The fact is that Vista is pretty nice, and in the end it's about using the right tool for the job. For most desktop users, Windows (Vista or XP) is the right tool (or at least better than Linux).

Operating systems are tools, not a religion.

Somehow, some way, it became "the thing to do" to bash anything that comes out of that big evil corporation in Redmond. I have been using Windows since Windows 3.51 (Also been using Linux since RedHat 9 and then Fedora as well as Mac OS 9 and the several mini-versions of Mac OS X), and Vista is the most stable Windows I have used.

It became so fashionable to bash Vista that I hear people all over who've never even used the OS saying how much it sucks. I've used Vista for over a year now and I can honestly say my computer has NEVER frozen to the point that I have to push the reset button. I couldn't say that about XP, at least not with a straight face. I couldn't even say that about, dare I say it, the beloved Mac OS X.

Agreed, it has some annoying features (User Account Control, anyone?), which I turned off the minute I installed it on my desktop. Also the fact that the UI changed so much made it difficult at first to find features in the places I was used to finding them. But that is just a problem of the user adapting to a new UI rather than a design issue.

The truth is, Windows hasn't really "sucked" since Windows ME, and Vista is a far superior OS than XP, regarding memory management, stability, storage management, security, usability, aesthetics, etc, etc, etc.

So before you jump in the "Vista sucks (I read it on the Intarnets)" bandwagon, make sure you try it with an objective mind and see how it is lightyears ahead of XP and any Windows before it.

I switched to OS X a year and a half ago and I have to be honest, it's a huge breath of fresh air. I still have a PC on the side to run certain Windows programs, but I'm staying with XP.

I have been wanting to make to cross for quite some time but much of the software I use for internet marketing s windows only one of these days the conversion will come lol

I am so happy that there is shadow copy, it has enabled me to save my computer twice after two failed Vista updates. Just rolled back to the last known good and all fixed. Vista can have my 15% anyday

I love shadow copy. Though i get paranoid about disc space there isnt anything for me to worry about still have over 300 gig free.

I just wish they had better shadow copy options in the future, such as only keeping a current shadow copy on your PC and allowing you to transfer the additional copies to a file server.

the more I read about Vista the more overcomplicated and annoying it seems. I just switched and am trying to get used to it. I already made my speakers complete disappear out of my comps total thought and existance once and I'm still not sure how I got them back. I miss xp!

Thanks for the details over where the space can go.
System Restore is a big resource hog, I just ended up freeing about 30GB of space from my 250GiB (= 232GB?) disk, otherwise I was down to around a GB or two and being pestered to erase files all the time.

Features on Vista are there for a reason, people only realise that when they have their head in shit; not the I'm saying Vista would work with guarantee, but it works most of the times. But their coders aren't very good with managing resources efficiently, I bet the linux guys could do it better.

Hi Brian , thanks for the Vista resource overview , I may have to pinch some for my site! I'll give you a link of course!
As far as the recovery partition goes , the data in there is hidden and if something does go wrong , if you didn't burn it off when you first started Vista , you are buggered , you cannot access it . This is a stupid thing to do , it should have been done so that it has a dual boot to the recovery section as a secondary boot,that way you can always access your files , without removing the hard drive, you can't even burn a recovery/install disk from the hidden partition, and as I am sure you know all bought computers , with Vista preinstalled , don't come with a recovery disk , you have to phone the customer servives and see if they will let you have one,which is damn cheeky , I mean you paid for the disk , so why not ship it with the pc!
I always run a dual boot with my second install on a second partition at the end of the disk ( where ther access is slow)only about 3gb, and configur that to be the second boot section, it allows a second working boot to allow access to the system files on the main boot , should anything go wrong, it has saved my OS so many times, easy access to the sam , system files etc!
The problem with the vista pre madee recovery is that you have to burn the disk on first start up , how would you know that ? You have to read the instruction manual!
Well you does that , anyway!

Thank you for this wonderful explanation. I'm going to pint this out and keep a copy on my desk so I don't have to explain it to people anymore.

This are very informative post and I really enjoyed your blog. I know that this that takes a hell of a lot of space on a hard drive, thanks for informing me about this.

Interesting read Brian, I was wondering where all my space went on my vista machine. This good I was going to use disk compression to fix it and that would of took up alot of system resources, now I can just kill the huge shadow copy...

Don't forget to read the last paragraph. If you don't need that space right now, do not remove Shadow Copy. It's an extremely valuable service, and if the only reason you are getting rid of it is because you don't like the idea of it using so much space, change your idea. Alternatively, you could reduce the amount of space that it's using.

I also seemed to be having the same problem, but for different reasons. I actually record a lot of webshows - or at least I used to using my webcam. These shows were automatically saved to my Vista machine causing the space to be used up quite quickly. Especially since it was recording in 1024x768. Taylor Thompson

i have vista installed and all my disc is full, i havent even one game installed, where are my GB?

I have to do most of my work on my Mac, but every once in a while I run across a program for PC only; Vista is frustrating me...not really sure why I switched. And is definitely a fat cat!!! my disc is always full too! Thanks for this tutorial...will really help me resolve some issues!

Are people really starting to have issues with finding space on their computers as of late? It seems as if almost anything you buy has more space than one could ever use up in a lifetime.

Of course, those of us who have an email marketing software that we have all over the place among tons of other programs and I suppose space disappeears in a hurry.

Thanks for the great info.

We see it all the time while out on site. People have huge hard drives and no space. People load GB's of temp files from surfing the internet. Most people choose to just let programs run when downloading and think it will not be stored on their HD that way. Clearing all temp files usually will give you a lot of space

thanks for the great explanation on "where'd my disk space go". several of these i was aware of, but many of them i did not know/appreciate. there is a lot of mis-information out there about vista, and this helps clear some of it up.

I've had a new Dell Inspiron 15 for about a month now. It's Vista Home Premium SP1 and it really is a nice machine and the OS isn't exceptionally disagreeable. Only problem I've noticed is the fantastic amounts of free space that goes missing for no reason. I put my computer online once and got smacked with three tracker spyware cookies that I happily disposed of. I know that the little devils are gone and that they didn't propagate, since the volume of disappearing data would be much more notable.

All the same, I've noticed that a GB at a time is disappearing from my hard drive, over a period of a few days to a week. I have 134GB total with 108GB open; that's down from 112GB just four days ago and down from 109 two days ago. It happens intermittedly and in small quantities at a time and I do run disk cleanup and defragmenter. Queer thing is, I ran defrag and that's where I went from 112GB open to 109GB; disk clean up for shadow copies, TEMP files, thumbnails, ect hasn't reclaimed my storage space to date.

Is it possible that Vista's just eating up my free space in shadow copies? Like I said, I KNOW the spyware's gone and that it wasn't propagating to begin with (it was confirmed as keystroke and behavior trackers for commericial statistical purposes). I'm really quite good with computers, but this Vista thing's just confounding me.

I want my free space back, damnit.

Yes, it is probably Vista shadow copies, and as stated in the main post, there is a limit and it will stop taking space once it reaches that point. Also, don't worry about cleaning temp files and especially defragging, it will not help with free space on this level. You might clean it once but it will just get used again right away.

In the first few days/weeks is when Vista takes all the space, then it stops. Just keep an eye on it and if you're still losing space in a month or so, then maybe there's a problem. You should use "windirstat" as mentioned in the main post as well. You still have over 100GB free space, so don't worry about it until you're down to 25GB or so.

PS. "Tracking cookies" are not spyware and cannot take up more than a few KB of disk space. All the spyware tools claim to find them, but they are really, really low risk. So much so that it's not worth worrying yourself about them. They are not software at all, just a data file and cannot do anything on their own.

I heard something about Windows and that it creates more and more directories, which soon take up all of your disk space. I thought this is what happens? Nice Article!

Sounds like whoever told you that is making stuff up. There are programs that create temporary directories and often do not delete them, but that is not something to be blamed on Windows -- that's just normal system operation.

I know you've had this up for a while, but I just thought I'd mention it's one of my favorite posts to refer people to that like to complain about Vista taking over their HD's! :)

Very informative for new Vista users.

I've been using Vista since beta and I can tell you it has matured into one fantastic OS, sure it takes up more HD space then XP, but then if you've bought your PC in the last couple years you probably have a HD that can handle it without any issue.

And if your 500GB HD is full, I recommend to most people to delete at least a couple of those pirated movies they downloaded, and watch all that HD space come back! ;)

I'm glad you found my post useful. Yup, it's been a while, but this is really a reference guide instead of a newsy blog post. It doesn't really expire (except maybe that I talk about 160GB drives, which by now might be on the small-side). I'm sure when Windows 7 comes out, there will be a new set of issues and complaints with it using disk space, so we'll see if I need to update it then!

I have a HP Pavilion Slimline with an AMD 64 Processor using Windows Vista. My problem is I can't control what I want on my "personal" computer. I had a Compaq before and was able to clean up a lot of junk that I never used or intended to use. Unless I allow open access to the whole computer thus eliminating some safeguards, all I can see is what is in the "Becky" files. I am unsure if this is HP or the Vista program but I would much rather use my Compaq because it is not a total "secret" to me what is on it. Is there a way around all the crap? I have tried to delete several items that use foreign languages, even signing on as the administrator but to no avail. I wish I had stuck with my Compaq and had an Ethernet card installed. Is that possible?

I'm not sure what you are asking, but Vista is different than Windows XP, and it organizes files differently. I think you may need to get used to the new organization, or you may have some other programs on there that try to make the computer more friendly for you. Either way, it's hard to tell what you are actually seeing based on your current description of the problem.

Just moved to Vista preloaded on a new computer and was given a Windows 7 upgrade disk. Have not upgraded yet because the Windows 7 advisor says some of my hardware and software will not work on 7. All of my software and hardware is working on Vista Home Premium.

I ended up here because I was concerned about the 'missing' 107GB on my C drive (750GB (697.5GB actual)). The drive shows 44GB used with 540GB free. 14GB is partitioned off as recovery drive D.
The Shadow Copy explanation removes that concern. Every GB is accounted for. Thanks for that Brian.

I'd been using XP forever and but after only a few weeks I think am falling in love with Vista. I guess I am a fickle person after all.

Grecat articles and it's so helpful. I want to add your blog into my rrs reader but i can't find the rrs address. Would you please send your address to my email? Thanks a lot!

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