Disk Management - Shrink Partition

How to Shrink and Create a Partition with Disk Management in Vista
It is possible in Vista to repartition your hard disk by using the Shrink feature in Disk Management. You can shrink an existing partition (volume) to create unallocated disk space, from which you can Create a new partition (volume).
How to Shrink and Create a Partition with Disk Management in Vista

information   Information
It is possible in Vista to repartition your hard disk by using the Shrink feature in Disk Management. You can shrink an existing partition (volume) to create unallocated disk space, from which you can Create a new partition (volume). For more information, see: Windows Help and How-to: Partition and Understanding Disk Partitioning

Partition Type


Primary Partition

A type of partition created on a hard drive that can host an operating system and functions as though it were a physically separate hard drive. Also called a volume. Only up to four primary partitions, or 3 primary partitions and 1 extended partition can be created on a single hard drive. Primary partitions can be used to install and start an operating system. If you want to create more than three partitions, the fourth partition is created as an extended partition. See: Windows Help and How-to: What are system partitions and boot partitions? and The Storage Team at Microsoft - File Cabinet Blog : Understanding the error message "There is not enough space available on the disk(s) to complete this operation" when you create a volume

Extended Partition

A type of partition on a hard drive that should be used if you want to create more than four Primary partition. Extended partitions can contain multiple logical drives that can be formatted and have drive letters assigned to them. An extended partition is a container that can hold one or more logical drive. Logical drives function like primary partitions except that they cannot be used to start an operating system. This option has been removed in Disk Management for Vista. For how, see: The Storage Team at Microsoft - File Cabinet Blog :How to create an extended partition in Windows Vista (Click Yes for Security Information)
warning   Warning
You will not lose any data on the partition (volume) that you are shrinking. You must be logged on as an administrator to perform these steps.
Tip   Tip
The default location for Disk Management is C:\Windows\System32\diskmgmt.msc.

EXAMPLE: Before and After with a New Partition Volume

To Shrink a Partition

1. Open the Control Panel. (Classic View)​
A) Click on the Administrative Tools icon.​
B) Click on Computer Management.​

2. Click on Continue in the UAC prompt.​
3. In the left pane, click on Disk Management under Storage. (See screenshot below step 4)​
4. Right click on the volume (EX: C:\ ) your want to shrink and click on Shrink Volume.​

5. You will now see this for a moment. (See screenshot below)​
NOTE: It is verifying that there is enough free space on the disk to create a new partition.

6. Enter the amount of space in MB (1024 MB = 1 GB) to shrink by, from the available free space on this volume, for the new partition and click Shrink. (See screenshot below)​
NOTE: The value in the Total Size Before Shrink box indicates the current size of the partition and the value in the Size of Available Shrink Space indicates the maximum size that you can allocate to the new second partition.
warning   Warning
The size of the available space can be restricted by the amount of space currently allocated to on the hard drive for the virtual memory page file, System Restore max size, and hibernation files. The location of the files on the hard drive plays a big part here because these files are marked as unmovable, and Disk Management is unable to relocate them. As such, if these unmovable files are located in the middle of the total amount of free space on the disk, then only the amount of free space on the other side (to the right) of these files will actually be available for the new partition. This will result in you showing that you have x amount of free space, but not being able to use it for your partition. The only way around this is to use a 3rd party hard drive partition management program, or setup the partition when installing Vista.
warning   Warning

If you wish to force the partition to shrink, then see: the How-To Geek: Working Around Windows Vista's "Shrink Volume" Inadequacy Problems

7. After a few minutes, you will see the new unallocated (unformated) partition. (See screenshot below)​

To Create a New Partition from Unallocated Space

8. Right click on the new Unallocated partition and click on New Simple Volume. (See screenshot below)​

9. The New Simple Volume Wizard will now appear. Just click on Next. (See screenshot below)​
NOTE: This wizard will make the new unallocated partition usable when finished.

10. Enter the volume size you want for the new partition and click Next. (See screenshot below)​
NOTE: Unless you are going to shrink this new partition, you should use the Maximum disk space in MB.

11. Dot Assign the following drive letter. (See screenshot below)​
A) Select a drive letter for the new partition.​
B) Click on Next.​

12. Dot Format this volume using the following settings. (See screenshot below)​
NOTE: This may take a while to format the new partition volume.
A) Enter a name for the new partition under Volume label.​
B) To save time, check Perform a quick format.​
C) Click on Next.​

13. Click on Finish when the Succesfully Completed window pops up. (See screenshot below)​

14. You will now see the Disk Management console with the new partition volume ready to be used. (See screenshot below)​

15. Close Computer Management.​
16. Click on Computer in the Start Menu and see your new partition volume. (See screenshot below)​

That's it,

Last edited by a moderator:
Shawn Brink



Do you have any kind of drive encryption enabled, or some security program that may be blocking this action?

I must admit that I do not know what else would be causing you to get the "Access Denied" message when you are only trying to shrink the drive by 30 GB. :confused:

I'm not sure... I'm not running anything that I know of that would block it. AVG Free and Spysweeper, and the built-in Windows security programs are all on. My hard drive is a Hitachi 320GB, 7200rpm, 16 MB, SATA-II if there might be something built into that (not sure of the model number but I can find it for you). The only software I've installed are games and patches, Steam, Core Temp, and RivaTuner. I've only updated my graphics drivers over the five months I've had the machine... this is the first time I've tried to do anything technical.
Ok Carey,

Give this a try using a elevated command prompt to see if it will let you shrink the C: drive by 30 GB (30720 MB).

1. Open a elevated Command prompt.

2. In the command prompt, type diskpart and press Enter.

3. In the command prompt, type list volume and press Enter.
NOTE: Make not of what volume number your C: drive is. It will probably be Volume 1.

4. In the command prompt, type select volume 1 and press Enter.
NOTE: Substitute 1 for the C: drive's volume number (step 3) instead if it is different.

5. In the command prompt, type shrink desired=30720 and press Enter.
NOTE: If successful, you should get a "DiskPart successfully shrunk the volume by: 30720 MB" message back.

6. In the command prompt, type exit and press Enter.
7. Close command prompt window.

8. If successful in step 5, you can now pick up at step 8 in this tutorial to finish creating your 30 GB partition.

Hope this helps,

Tried shrinking in the fashion described, but access still denied. Ran as Administrator both times I tried. Since its the weekend I might go ahead and format, reinstall Vista, and partition the disk from there. Then again I don't really need a partition... but 30GB of unallocated space so the Ubuntu installer can pick it up. Do you think a format would clear up this problem for me?

Ironically enough, last night I installed Ubuntu inside Windows to run as a virtual machine and that doesn't work either. It only added an entry to the Vista bootloader and says its missing files when I try to load. I can't be sure, but I don't think this was meant to happen for me! I'll gladly try any other suggestions you have before I get started on this though. I await your advice my good sir. :D

Carey, it sounds like you may have some sort of permission issue, so formatting and reinstalling Vista should fix the problem.

I do not know what else to try other than a reinstall though. :(

I hope it goes smoothly for you.

Cool, I'll go ahead and proceed. It's something I need to do anyway - if I don't, this will undoubtedly cause more headaches in the future. Thanks for all your help! I'll post back and let you know how it went, good or ill. I don't look forward to updating all my Steam games though. Can't back up those patch files!


Success! After I reinstalled Vista it shrunk without any problem. Now I just need to go out and grab some CDs... apparently the one I burned the iso to is unreadable and I'm all out of blanks. At least its working fine now. Thanks for all your help!

This looks like the perfect place to ask this question:

I partitioned my HD and created a new volume with 85GB. I partitioned 45GB unallocated space and tried to extend the 85GB with it but the 'extend volume' button was grey so I thought of deleting the volume and somehow extend it with the 45 that way. Afterwards, the 85 turned into free space (green) and when I try to delete this partition, there's a message saying it won't be accessible if I delete it. Now I'm scared of deleting that free space and I don't know what to do from here... PLEASE HELP!
Hi Joker87, and welcome to Vista Forums.

Could you post a screenshot of Disk Management with the mentioned partitions? This will help us better understand your situation for a hopeful solution.

Oh I never thought Brink you would answer so quickly :D this makes this website worth wild! I was trying to free up more space by doing the Dell Image Restore. It did freed up like 40GB more so now I have 80GB unallocated.

I'm trying to get 50GB on C:, leaving 10GB on my recovery and the rest as a new partition/volume (sorry, I don't really know the difference between terms)



Yes, you can safely delete the 84.77 GB extended partition to do the above. You can only create 4 normal partitons on one hard drive, so you will not have access to the deleted 84.77 GB extended partition until you extend the 79.87 GB partition into it from the above post.
Thanks Brink!!!!!! I tried working on this for almost the whole day, and you helped me within 30min!! thank you~!!~!! :Dx2
Hello Shawn !
Once again, I need your help with the Drives on my computer. My brother thought he had the ability and skill to mess around with the computer drives. It worked out fine BUT now it leaves me with some questions that needed to be answered. So I come to you for a little clarifications if you don't mind Please see screenshot below:

There are 4 drives on my computer. C:, D:, E: & F: My questions as follow:

  1. Which one is the hard drive (please excuse my ignorance) and which one is the partition since C, D, E are all says Partition.
  2. The C: status says System and D: status is Booting. Please clarify for me. I'm confused. Also, when I download a program\application, it will go to the D:\program files. So what is the C: drive for and how do I put it to use?
  3. Finally, what is the difference between a partition and a volume?


Hello Bennys,

1) From what I see here, it looks like F is your DVD drive and C, D, E are separate partitions on the one hard drive. D is your Presario Recovery Partition.

2) I'm not sure exactly what C and D is for. One is your Vista installation, and not sure what the other one is. Are you dual booting with another operating system on C or D?

3) This link will help tell you the difference between a partition and volume.

Hope this helps for now,