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Published on 10.12.07 by Brent Trahan

Extend a Volume in Windows Vista

How-to increase the size of a volume (drive or partition) in Windows Vista.


This guide shows you how to make a volume (drive or partition) larger in Windows Vista by extending it with unallocated space. The unallocated space can be on the same hard drive as the volume you want to extend or it can be on another drive, although I don’t recommend using separate drives.

For example:

  • Let’s say you have a 100GB hard drive but your C: drive is only 50GB. You can take the other 50GB and add it to the C: drive making it 100GB instead of 50GB.
  • Let’s say you have an 80GB hard drive with the C: drive taking up all 80GB. You can purchase another hard drive that’s 100GB for instance and extend your C: drive to use the new 100GB hard drive making the C: drive a total of 180GB. I personally don’t recommend this though.

Unallocated Space Only

You can’t extend a volume with the space of another volume that’s been formatted. You need to delete the volume (which will delete any data in it) and use the unallocated space of the deleted volume to extend the volume.

For example: Many computers come with a 100GB hard drive, but the C: drive is only 50GB and the E: drive has the other 50GB. You’ll need to delete the E: drive and use it’s unallocated space to extend the C: drive.

Warning: Most OEM computers (Dell, HP, so on…) come with a hidden or extra partition that has a backup installation image saved on it instead of sending you CDs or DVDs (it saves them money). If you delete this partition and you need to reinstall or fix Windows Vista, you’ll have to purchase disks from your computer’s manufacturer.

Delete a Volume

If you need to delete a volume, right-click the volume you want to delete in the Disk Management section of Computer Management (see steps below on how to open Computer Management) and then click Delete Volume. All data that is in that volume will be gone once it’s been deleted.

Extend a Volume

  1. Right-click Computer in the Start Menu and then select Manage.
  2. Click Disk Management under Storage on the left of the Computer Management window.

  3. Right-click the volume you want to extend and then select Extend Volume.
  4. Click Next on the welcome screen.

  5. If you have more than one volume that has unallocated space they’ll show up on the left side of the Extend Volume wizard under Available. Click the volume(s) you want to use to extend the volume with and then click Add to send it to the right side under Selected. If you only have one volume of unallocated space it’ll show up on the right side for you.

    Note: You can extend a volume using unallocated space on a separate disk (example: the C: drive’s total space consists of space from two hard drives), but I don’t advise doing that. If one disk crashes, the whole volume goes down with it.

  6. If you don’t want to use all of the unallocated space from the volume you picked, change how much space you want to use in MB next to Select the amount of space in MB.

    Note: 1024MB = 1GB.

  7. Click Next.
  8. Confirm your settings and then click Finished.

The volume that was extended now includes the unallocated space.

Still need help? Ask your computer question now.

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19 Responses to “Extend a Volume in Windows Vista”

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  1. Malcolm says:

    thanks a million , worked a charm !

  2. Jeremy says:

    Thanks a bunch, that worked great.

  3. noah says:

    I can’t select “extend Volume”;
    I have 2 partitions 10gb and a 217 and then i have 5gb of unallocated space. I cant upgrade anything because i made the partitions too small for the main patition(10gb) so i can’t update my drivers…

  4. Brent Trahan says:

    Which partition are you trying to extend?

  5. Lisa says:

    if only it were so easy…i am trying to extend my c drive (came from the factory as only 30GB, which is now nearly full). i have a d drive that is 150 GB, mostly empty. when i right-click on C drive in the disk management, extend volume is grayed out. i “shrank” D by 20 GB, making it unallocated, but i still can’t extend C into that. extend is still grayed out. according to this post, it seems like i need to delete the D entirely then try to extend the C. is that true?

  6. apai says:

    why cant i extend my C drive?i already delete my D drive entirely but still the extend on C drive grayed out.

  7. Doug says:

    Thanks!! I thought I was looking at hours and hours of work, but the longest thing was formatting the new volume. I just surfed a while, and it was done.


  8. Toles says:

    I can’t extend my c drive,too. I deleted my d rive but ? can’t extend c drive it was still grayed out

  9. Karthik says:

    Hey thanks. It works all right! But only when you format D: drive completely, can you extend or shrink the C: Drive or even create a new drive!

  10. Rahul says:

    I have 60 Gb that shows as “free space” and is green. I cannot extend that into the C as it is grayed out. If i try to delete it shows a message saying this partition will become inaccessible. Should i delete and if i do will that make it say unallocated? Please help.

  11. Raj says:

    Thanks a Lot.. its working..


    Thanks & regards


  12. varun says:

    Does anyone know how to extend local disk C…. I have 80GB hard drive with only 20GB to my local disk drive and 60GB to my D drive. However even after shrinking the volume of my D drive to say e.g. 15GB less, i cant extent Drive C ….Is there any way i can add this 15GB or more to my Local drive C….have tried everything….

  13. Elaa says:

    Varun am also facing the same problem
    Are you solved the problem?

    Please help me….

  14. Jerry says:

    I cut another part of my C drive to add it to my D drive, but i hear you cant extend to the left with the built in manager. Is there any free software you can recomend to do this?

  15. abhinav says:

    i have the same problem, i cant select extend drive?? what do i do? please help

  16. christian says:

    sometimes using diskpart helps. theres plenty of sites on how to do this in detail. ill try to explain in short. open run. type diskpart.exe. youl get a command prompt window.

    type “list volume” if you only have one hard drive ( i am basing
    this off the assumption you do)

    type “select volume (the number of the volume you want to modify
    without () )”

    if you have unallocated space go ahead and type “extend size=(number in MB)” and hit enter.

    if you do not have unallocated space. find a volume with other than the one you want to extend and have some extra space on.

    do this by typing “list volume” when the list populates type “select volume (volume number you want to select wihtout () )”

    type shrink size= (however much you want to shrink) and hit enter
    10000 mb is 10 GB.

    now follow the steps at the top for extending a volume.
    list volume

  17. websvr says:

    Thanks, it’s good article.
    Also here is an instruction: http://www.extend-partition.com/extend-system-boot-partition.html

  18. may says:

    dont be silly guys
    this article is wrong!!!
    i am 200% sure you wont be able to extend your C drive by following these steps. yes you can extend other none sys drive, but not with window installed in it

  19. Smithers says:

    TY so much. this helped a bundle.

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