How do I use an “unallocated space” partition in Windows 7?

Unallocated space as a hard disk partition is space that won't be used. I'll look at the two common ways to make unallocated space usable.


What does “unallocated space” on a hard drive mean? Is it just sitting there, waiting to be used when needed or what? My hard drive is now divided into two halves of 250GB each. I would like to have the whole hard drive clean and free. I searched your archives but there is nothing on deleting a stuck partition.

Well, in a sense, it is just sitting there, waiting to be used. The problem is that it’s waiting for you to tell it how it should be used.

Basically, you have an empty, unused partition and you need to decide how you would like that space to be used. Then, you need to tell Windows to use it.

Fortunately, this is pretty simple in Windows 7 and doesn’t require any additional tools; basic partition management and rearrangement is built right in.


Fire up the disk manager (right-click Computer, click Manage and then click Disk Management), and I’m guessing that you’re looking at something similar to this:
Hard disk split into three partitions, one of which is 'unallocated'
That line represents a single physical hard disk that is divided into three partitions:

  • System Reserved – You may have something like this, a recovery partitions, or perhaps nothing at all.
  • C: – This is the partition that contains your C: drive.
  • Unallocated – This is the partition in question.

That unallocated partition represents disk space that will not be used until you allocate it. There are typically two approaches.

Format it as an additional drive

A very common approach is to simply create a new drive out of the unallocated space.

Right-click that Unallocated drive and click New Simple Volume…
Create a New Simple Volume out of unallocated space
This starts the “New Simple Volume Wizard”. Click Next on the resulting dialog to be taken to the page where you specify the volume size:
Specifying the size of the new partition
The default answer is to use all of the available space, which is probably what you want. If you want to break the unallocated space into multiple drives, you might choose a smaller size.

Click Next and you’ll choose the drive letter to be assigned to the new partition:
Specify the drive of the new partition
Once again, the default is probably appropriate, unless you have a specific reason to change it.

Click Next and you’ll specify formatting options:
Specify the format of the new partition
The answers to the default are typically appropriate, although this is a good time to specify the Volume label.

Click Next to get a summary screen for confirmation, and then Finish to complete the operation. Windows then formats
the drive and when complete, it appears as “just another drive” on your system:
New E: partition in disk manager
You can begin using the new drive immediately.

Expand the adjacent drive

The other approach, which in previous versions of Windows required third-party tools, is to simply expand an adjacent volume to use the unallocated space.

In our example, we’ll right-click the C: drive, and click Extend Volume…
Extend Volume option on C: drive
That option should only be available if there’s room to expand – meaning that there’s an unallocated partition following the C: partition.

This time, we’ll start the “Extend Volume Wizard”. Clicking Next takes you to the “Select Disks” dialog:
Extend Volume section dialog
This somewhat confusing step is all about selecting which partitions on the disk are to be added to the volume that we’re extending. The good news is that in this simple and common case – an unallocated partition immediately following the C: drive – the dialog is pre-loaded with default choices that are probably what you want: extend into the entire unallocated partition.

So all we need do is click Next.

A summary screen confirming our choice appears. Click Finish, and Windows begins the operation.

When complete, the unallocated partition is gone and the C: partition is larger:
C: partition extended to encompass the entire drive


  1. dr d b karron

    the problem is that some disk types max out and won’t let you use the unallocated space.

    I am trying to figure out how to overcome the 2TB restriction on System Active Primary Partitions. I removed windows from it but it still won’t extend.

  2. Robert Tankersley

    I have a partition labeled Healthy, Primary Partition with 12 GB showing use is 0%. Right click only give on active menu item — Delete Volume. What is that partition and is that 12 GB really unused?

    It probably is exactly what it looks like – an unused empty partition. My guess is that you’re not running Windows 7 since the menu shows no partition management options. (Or perhaps it’s a partition that Windows 7 can’t manage for some reason.)


  3. Dr VB Mathur

    Works fine for most computers. But a new Laptop sometimes refuses to create a new simple volume saying that the maximum number has been reached. The machine suggests you craete a dynamic volume instead. A user like me ( a non-techie) does not know what this means and what it would do. This possibility remains unanswered by you and I look forward very anxiously for a solution.

  4. Snert

    I’m still using XP Pro until I HAVE to go to Win7.
    Any advise?

    For Windows? Only that Windows 7 isn’t that bad once you give it a chance. For partition management? Easus partition manager.


  5. Peter Simmering

    @Snert: buy a commercial product like Partition Magic (Shareware, not free) or look for a free product at your own risk.

  6. K Whisenand

    Re comment by dr d b karron at August 9, 2011 8:17 AM. I have the same problem and I have Win 7 64 bit and hav this section on my 2nd internal hard drive which has two partitions plus the healthy primary partition which I can’t I can’t do anythng with except Delete Volume and I don’t know what would happen if I deleted the volume. Would it just affect that healthy primary partition or would it affect all partitions on that drive?

  7. Jake

    I have 410Gb of “Free Space connected with my Healthy Boot partition (i.e., the “C” drive). Whenever I tell disk manager to create a new volume out of this space, it walks me through the steps and then tells me there’s not enough space to perform this action (I’ve tried using he max indicated amount of space and several smaller allocations and get the same result every time). Any idea why I can’t use this “Free Space”?

  8. pradeep shne

    i had partition the system hardisk, which has the 450Gb. while partitioning the drive which shows like you cann`t create a new volume in this unallocated space because the disk already contains the maximum number of partitions..

  9. rodjoju

    Hi, Leo!

    Your article about the unallocated disk space is really great. it’s easy to follow. Here’s my problem… I followed exactly the first way. but in the end my laptop said this, “The operation you selected will convert the basic disk into a dynamic disk. If you convert the disk to dynamic, you will not be able to start installed operating systems from any volume on the disk (except the current boot volume). Are you sure you want to continue? YES/NO”

    I clicked yes. It returned another message that said, “Dynamic disks are not supported by this operating system or server configuration. Dynamic disks are not supported on clusters. YES”

    I just clicked yes.

    In the end, I still have the 149 GB unallocated. I just want to use this because i am running out of space in my C. I hope you can help me further on this.

    thanks in advance.

  10. rodjoju

    By the way, Leo… I also tried the 2nd way you stated in this article. Unfortunately, when i right-click the C to expand its volume (hoping that the unallocated could be transferred in C), the ‘extend volume’ and ‘delete volume’ are unclickable. Only the ‘shrink volume’ is clickable. Oh please, please help me. Thanks.

  11. Ducky

    You mean, when my computer was telling me I didn’t have any more room on my C drive, I could have extended it by reallocating one of the other allocated drives?

  12. payam azimi

    You told us how to creat a primary partition out of an unallocated partition
    My question is taht how can we create three new logical partition out of the unallocated space ?

    Simply select a size smaller than “everything” when creating the partition, and then repeat the process with the leftover free space.

  13. sandeep

    Hey “rodjoju”, I am facing the same problem as you did.

    “The operation you selected will convert the basic disk into a dynamic disk. If you convert the disk to dynamic, you will not be able to start installed operating systems from any volume on the disk (except the current boot volume). Are you sure you want to continue? YES/NO” ……

    Any solution to this? please keep me informed, urgent

  14. Pratik

    i am facing the same problem as rodjoju and sandeep that the basic disk will be converted to dynamic disk. please help as i have no clue about what to do further and i m having 212 gb of unallocated disk space..

  15. Jamie

    So, one of my disks is set up basically the exact same as your example (Sys. Reserved; Drive; Unallocated Space. Only difference is it’s 3TB) but both my “Extend Volume” and “New Simple Volume” buttons are greyed out.
    Now I’m missing out on ~750 GB of space, and it’s a little frustrating.

    Running Win7 64 bit, hardware inside is top-of-the-line (Or damn close), all updates have been done, no viruses / spyware. (Hardly any -ware at all, it’s a fresh system.)

  16. computerecovery

    re.) the warning in Win7 : “The operation you selected will convert the basic disk into a dynamic disk. If you convert the disk to dynamic, you will not be able to start installed operating systems from any volume on the disk (except the current boot volume). Are you sure you want to continue? …

    If you are trying to recover space to reformat an entire drive as one partition and run into this problem, you might try this…

    In Disk Management, first
    -Create a new Simple Volume in the Unallocated Space.
    -Keep the new Volume and Delete the Old Volume .
    – Extend the new Volume into the Unallocated Space

    Done! :~)

  17. Gurjeet

    My d: drive is my hp recovery disk. update my recovery because my recovery is very old and some missing updates. but my d: drive is delete then i create new d: drive. then i will try to create recovery disk but system shows error ” a set of recovery disc has been created for this pc. only one set is allowed per pc. please help

  18. Ken

    My BIG question is “What happen’s if I click Yes after the message: “The operation you selected will convert the selected basic disk(s) to dynamic, you will not be able to start installed operating systems from any volume on the disk(s) (except the current boot volume). Are you sure you want to continue? Yes / No” ???

    Will I then Not be able to boot windows on my PC?

    Note: All I want to do is add the 465GB of “Unallocated space” to a usable partician.

  19. Noel

    Hey Leo im from Philippines.

    my 1TB HDD has 3 main partitions (not including system reserved partitions)

    C: is my windows (290 GB)
    E: is my my movies/song etc. (512 GB)
    i have Unallocated partition (110GB)

    since unallocated partitions cannot be merged to NTFS partitions, i have used the unallocated paritition to create a new partition called F: which is now 110 GB.

    while the merging process is about to complete, i get an error saying:
    “Not enough unallocated space before and after the selected partition for the move/resize feature.

    btw, im using EaseUS partition manager. can you help me with this?

  20. Rick

    Hi Leo,

    Thanks for putting up this.

    I have an IOMEGA 500GB external drive, only around 1 year old and not frequently used.

    Recently I did some back up of my files. When thats done, I kept the drive. When I plugged in again, the drive is no longer accessible from My Computer. I am using Windows 8 Desktop environment.

    I did a google search and found that I have to select a drive letter. However, I left click, right click, still dun have the option to do that.

    In my Safely Remove Hardware icon, I can see “Eject IOMEGA HDD”. That means my drive not spoilt right?

    I have since followed your advice on creating a new Simple volume, but i did not format the drive as it contains important data. Now that I have the J: back, i cannot access anything inside it unless i format it and lose all my data? What can i do to get back the data?

    Thanks a million.!

  21. Srinivas

    Hi Leo,
    I am using sony laptop. I have windows 7 and windows server 2008 r2 installed in dual boot. so i now I have 2 os partitions and a recovery partition. Now I want to shrink server 2008 partition(98gb), bcz i need a small partition to work on server. Till shrinking the volume, it is working fine but when I tried to create new volume on unallowcated space, its showing an error says “The operation you selected will convert the selected basic disk(s) to dynamic, you will not be able to start installed operating systems from any volume on the disk(s) (except the current boot volume). Are you sure you want to continue? Yes / No” ???
    so i dont want to loose the other operating system and yet want to create a partition.
    Could you please help me with solving the error…..thank you in advance.

  22. Eleanor

    Thanks! Worked a treat. I replaced a failed 32GB SSD with a 250GB SSD but system was only showing 30GB after installing system image. Checked in Disk Management and the rest was showing as unallocated space, so did the ‘extend C partition’ thing and it did the trick – now have the full volume available in C. Thanks very much for this very helpful article.

  23. Ankit kumar

    when I create new volume can I recover previous all data.I want not format local disk by creating new volume. how to do this please sent massages on my {email address removed}

  24. Ron

    Best explanation yet, because I was afraid to click ‘Finish’ until I was sure it wasn’t going to do something unexpected. But, I want to do a Move, so I have to expand on one side, then shrink on the other.
    I was hoping to see a few words about ‘Shrink’ — or a link to that information — did I miss it, or maybe it could be added? I’ll do a search of Leo’s entire site, just to make sure.

  25. umapathy

    I have installed win 7 and format for another drive it show unallocated space for 64GB, i have create or format the disk the below message is came” the operation is not enough space to completed” my hard disk 64GB is unused what i can do.

  26. deb

    i am trying as saying as above
    but after finishing it it’s Say’s there is no enough memory.
    but i give that how much have

  27. Darshan K

    When I am creating new partition with unallocated space below error message is prompting. so kindly help me out from this error
    “Error already have the maximum number of partitions, unable to recover unallocated disk space”

    other than complete system format solution

  28. Aravind

    I have something related, but the volume is shown as Free space in green label I can only male a new partition on it, (i cannot convert it into unallocated space and use it for another partition, i have a 1TB Harddrive having about five partitions incl.this one ) please help me retribe my space.

  29. Dennis

    Your advice on extending a volume C into a following unallocated partition is very clear. My set up is that the unallocated partition is BEFORE (to the left of) the C partition. (I had just XP but made a Win 7 dual boot and this is how the disk was arranged – D for XP, Unallocated, then C). How should I extend in this case? (Does extend = merge?)

    Thanks for advice,

    • You’ll likely need to use a different tool – probably something like Easeus Partition Manager. That’ll let you move things around so that they’re lined up appropriately for combining. Windows built-in manager is somewhat limited.

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