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Why the used space of C drive increases rapidly while using Vista?You are using your brand new Vista system, only finding the used space of C: drive has increased a lot. Even if you had reinstalled your system, there's still plenty of space found to be newly used a while later (even when there are only a few installed software). Why is that?

When you are using Vista, especially during the first month after the installation, the space occupied by Vista will increase by a certain degree. Generally, it is normal for Windows Vista to occupy 15GB to 20GB hard drive space。

Is it possible to release some used space?You can try the following methods:

Method 1: use "Disk Cleanup"

The system comes with a disk cleanup tool. It will be very helpful to run it regularly.

Method 2: Use the VSP1CLN tool to clean up SP1 backup

If you have installed Service Pack 1 (SP1), this information might be helpful. SP1 will back up some initial files, so that you can successfully uninstall SP1 if you want to some day. Cleanup of this backup information can save some space.However, after cleanup, you will not be able to uninstall SP1 any more!

  1. Start Menu -> In Start Search box, type cmd, then a cmd option will appear at the top. Right click -> to choose Run as administrator.

    A pop-up box will appear asking you to confirm. Click continue to confirm.

  2. In the command line window that displays, type VSP1CLN, and press Enter.

  3. Press y to confirm.

  4. Wait for a few minutes.

  5. A message saying the operation is finished will display after it finishes.

Alert: Do not know if your machine has installed SP1? The following simple steps will help you find out:

Start Menu -> In Start Search, type winver, -> press Enter. If Service Pack 1 is installed, in the upper part of the window, it will display build 6001: Service Pack 1.

Method 3: Use COMPCLN to clean up files of previous versions

If you have installed Service Pace 2 (SP2), you will also find that the disk space occupied by the system increases substantially; this is because the files from the previous version (RTM or SP1) are not removed completely when installing SP2. For this scenario, we can use COMPCLN command.

  1. Open the command window according to the above pictures. In the window, type COMPCLN and press Enter.

  2. Press Y to confirm.

  3. After the command is performed, the files from the previous version that are no longer needed after the installation of SP2 will automatically be removed, and approximately 1GB hard drive space could be released.

Method 4: Set up the space size of Volume Shadow Copy:

Vista uses the Volume Shadow Copy technology for data backup and system restore. It needs to occupy a certain amount of space. You can use the Vssadmin tool to set the size of occupied disk space. Specific steps:

  1. Start Menu -> In Start Search box, type cmd, and then a cmd option will appear at the top. Right click to choose Run as administrator.

  2. Then type vssadmin list shadowstorage and press Enter. (In order to avoid typing mistake, you can copy and paste)

  3. This command shows the current disk usage of volume shadow copy.

  4. In this command, Maximum Volume Shadow Copy Storage space represents the maximum space it can use (now it's 18.603GB). You can lower it appropriately to save space.

  5. The following command will be needed (in order to avoid typing mistake, you can copy and paste):

    VSSAdmin Resize ShadowStorage /For=C: /On=C: /MaxSize=1GB This command limits the Maximum Volume Shadow Copy space to 1GB. You can aslo set it to the size you want.
    When you see Successfully resized the shadow copy storage association, the set up procedure is done.

What the increasingly occupied space of C drive is used for?The space is used by:

  • Registry: The user data and program data are continuously written into the registry, so the registry size also increases.

  • Patch installation: When Windows Update automatic update is activated, there are new patches issued almost every month. Patch installation needs additional space. (New patches will replace some files while back up some original files.)

  • System restore: System restore will automatically create restore point, which needs hard drive space.

There are other things that consume disk space, but we will not list them here.

What if I come across with other issues during usage?

Relax, we have a post specially created for this article in Microsoft Community Forum,in oder for convenient discussion. If there's any problem, you can reply in the post.

If this cannot resolve your issue, you can browse the Forum for good solutions.

We look forward for you precious opinions and suggestions!

After you have used Microsoft Support and Help, if it is convenient for you, maybe you can spend a few seconds to grade this article in the feedback table at the bottom of this webpage, so that we can improve our work. If you have any good suggestions or thoughts, you can also fill them in the "additional comments". (For your problems to be resolved sooner, technical problems can be raised in the according posts of the Microsoft Community for discussion)

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