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


Re: Disk Management - Shrink Partition Problem

Hi Friends,

I bought a new sony laptop last week which was having Windows Vista Business Edition. I have totaly 200 GB hard disc space and I tried to make partition, as mentioned in the forum, i didnt used any third party software to make partion, I just right clik my computer->manage->disk management then I right clicked and clicked the shrink volume it showed a dialog box and it has automatically shown some space, i didnt specifed my own space size. I just accepted the size which it showed, then i gave shrink. and its showing 100 GB in C drive and 76 GB as unallocated. I want to keep only 50 GB for C drive but now it is having 100GB, Is ther is any possiblity of making reshrinking this process (ie can I make it as a old one having 200 GB space in c Drive so that I can do the proces again carefully using some third party softwares

Please reply me back

Thanks in Advance,
Hi Arun, and welcome to Vista Forum.

Extend C: back into the new unallocated 76 GB partition. If it is no longer unallocated then Delete the new 76 GB partition first. This tutorial will show you how to.


Afterwards, do this tutorial again to shrink C: , but this time type in how much available free space you want to shrink C: by (step 6) to have only 50 GB total left. (1024 MB = 1 GB)

Hope this helps,
Awesome...Honey, I shrunk the kid(C:/ only).
My D:\ is completely full. I have zero available space to shrink. What should I do now.
Please help.
LOL, I like that Bennys. :geek:

I would say about the only thing you can do is to either start deleting what you no longer need on the hard drives to create more free space, or get another hard drive to use. :(

They have gotten pretty reasonable here lately though for some of these larger 750 GB to 1 TB drives.
Thanks...I'll leave it alone. But why did it fill up so quickly? Is it because I ran CCleaner a few times and deleted the recommended file on my computer?
Anyhow, from ow on, where do the backup files goes?
If it is a Recovery Partition, then that is placed on there by the computer manufacturer (OEM). It is used for you to be able to do a clean install of Vista with. They are usually not very large in size. Some OEMs like HP has a HP Recovery Manager program that stores backups on this D partition. It would fill it up quickly, but it would delete the old backups as new ones were created when it runs out of space.

CCleaner would not have any affect on this partiton. Any file backups or System Restores you do in Vista would be stored on C: instead.
Please assure my understanding. The D: drive will always be backing up new files but in order to do that, it must clear the old ones for new arrivals and I should not be worry about it, correct?
Thanks for the info.
If you have a OEM computer that has a Recovery Manager type program, then usually it is only about the same as System Restore. It will not backup your files like you are wanting.

To Backup File Types:

If you have Vista Ultimate, Complete PC Backup:

3rd Party backup program you can try a 15 day trial period:
Complete hard disk recovery solution, backup, drive copy, clone and image computer software
Greetings all,

I'm trying to shrink my primary partition by 30GB to dual boot Linux but it's proven impossible so far for me. I have plenty of space to do so. I've tried using the Disk Management utility and also tried getting it done from the command prompt with no success. No matter what I do, I run into an "Access Denied" message. I've read that it works by booting into Safe Mode, but that didn't help. Nor did turning off UAC. I'm logged into the Administrator account. I've turned on the Administrator diagnostic account via command prompt, but still cannot shrink the partition. I'm ready to format, install Linux (Ubuntu 8.04) first, then reinstall Vista. I've read that Linux has excellent partition software though I admit to having no hands-on experience with it. Been trying to sort this out for a few days now and any suggestions/advice would be very much appreciated... am at my wits end here. Thanks in advance!
Hello Moriarty, and welcome to Vista Forums.

Could you post a screenshot of what Disk Management reports with your current drive layout? This may help us determine what may be causing the "Access Denied" and a proper way for you to do this.

Thank you,
Greetings Shawn,

Currently it shows C as the primary (and only) partition taking up all the space, 298.09GB. No unallocated space. I also have a DVD/CD-RW drive (D: ), and a 12-in-1 media reader (E:-H: ). Oh, this also is probably important; I purchased my machine from cyberpowerpc.com and had them pre-load my OS (likely a massive mistake). I have a sneaking suspicion it has a lot to do with that. This information may be prevalent as well; when I turned on the Adminstrator diagnostic account from the command prompt, the log-on screen, which before showed two Adminstrator accounts now only shows one. I took a look at the Event Viewer too and it showed errors which coincided with the times I was trying to shrink, but frankly, my tech level is nowhere near high enough to glean any useful information from it.

I'm at work at the moment but when I get home later today I'll post a screenshot for you. Great forums by the way, after reading over articles here for a month this site is what convinced me I wanted to try Vista. Thanks for the quick response!


Space is not an issue for me. I only need 30GB as I won't be using Ubuntu that much. I just want to fiddle with it. I'm not really interested in using third party software, firstly because I've read quite a few posts around the net saying the results to Vista MBR can be catastrophic, and secondly because this should be something I can easily do within Vista itself. I'm more interested in learning how to do it this way and solve my current problem. If it comes down to it, I'll have no other choice, but I'm confident I can get this resolved on these forums.

Thanks for the response,


I'm not sure if I successfully changed ownership of the drive. I followed the steps in the tutorial but, as illustrated below, TrustedInstaller isn't in any of the boxes except the owner. I went ahead and tried to shrink anyway without success.

Thanks, Carey




That would be where you would want TrustedInstaller to be. In the first image on the left, click on the Administrators (CRAY\Administrators) and see if you have Full Control checked as Allow.

Yes, Full Control is allowed. Actually, all three entries have everything set to Allow except Special Permissions if that is helpful.