I have a C: drive that is the primary partition (bootable) that I would like to extend. In order to do that it seems like I need to have Unallocated Space to the right of the partition.

Right now, I have "Free Space" to the right. How in the world do I make it Unallocated (not formatted)?

There must be some command line utility to be able to do this.

  • From the Help of Vista it seems like: "You cannot extend the current system or boot partition". Why not? – tzup Aug 25 '09 at 9:12

The problem is that you can NOT extend a primary bootable partition. I think your best bet will be to boot from a BartPE CD or a GParted CD, and do the re-size from there.

  • I'd recommend GParted I think most of the partition resizing stuff in Bart relies on commercial software. – Col Aug 25 '09 at 9:07
  • @Col: True, there are some free ones as well though (bartpe-partition-manager.qarchive.org) - no personal experience. – fretje Aug 25 '09 at 9:12
  • Gparted downloading section gives a 500 ... arghhhh – tzup Aug 25 '09 at 9:30
  • try this link: sourceforge.net/projects/gparted and click on the green download button. works for me... – fretje Aug 25 '09 at 9:58
  • K, that works. Hope the gparted approach works. (keeping fingers crossed). – tzup Aug 25 '09 at 10:42

You can use the command line utility diskpart:

  1. Launch a command line with Administrative Privileges (click the start menu, begin to type cmd, right click "Command Prompt" that appears and select "Run as Administrator")
  2. Type parted
  3. Type list volume and note the volume number of the drive you want to expand
  4. Type select volume n where n is the number you determined above
  5. Type extend
  6. Type exit

In Vista and Windows 7, this will work even on the boot volume and take place immediately.

  • Tried it, and got: "There is not enough usable free space on specified disk(s) to extend the volume". Well yeah, because its Free Space not Unallocated Space. – tzup Aug 25 '09 at 9:15
  • Okay so that comment doesn't make sense at all :) Problem is that even though I have some free space formatted as ntfs on the hard drive, the utility doesn't want to extend the volume c: with that space for the reason above. Go figure! – tzup Aug 25 '09 at 9:21
  • ok. so the layout is this: [C-Drive][another partition, but empty][other stuff]? in this case, delete the empty partition and then use the command above – pilif Aug 25 '09 at 10:50
  • @tzup In that case, use the Dell tool I mentioned. – abstrask Apr 18 '12 at 8:28

No need to boot up GParted or anything else but your Windows installation.

Use diskpart.exe's extend command as suggested by others.

If that however doesn't work, Dell has made a small utility do extend partitions on-the-fly. Even works on Windows XP/2003 boot partitions.


  • The reason why you can't extend the C: drive on Windows XP/2003 with standard tools is, that it contains both the system and boot files. At least with 7/2008R2 (maybe also Vista/2008, I don't know), a standard installation will create a small separate system partition. With the system partition no longer being the same as the C: drive, even that can be extended on the fly. A bit more info here: en.wikipedia.org/wiki/System_partition_and_boot_partition – abstrask Apr 18 '12 at 8:35

To make it unallocated, just right-click on that partition and select delete partition. That will also kill any data that you have there.

In case that you want to extend partition on other partition and you want to save data, try Partition Magic or similar program. Windows cannot do "non-destructive" extend.

  • Deleting the partition gives "Free Space" instead of "Unallocated Space" and this the C: volume still has the "Extend" option grayed-out. Bummer! – tzup Aug 25 '09 at 10:04

I think your best option is to do it from a linux liveCD, or a dedicated live software package like GParted. Personally, I just said "bleh" and set it up as a \downloads partition, so I could keep track of the slippery slope that loves to eat my hdd.


To shrink or expand partition size, use built-in Computer Management.
But on vista/win7, drive C: can't be expanded unless there is an adjacent unallocated space next to it.
To do this,
Shrink drive D:
Make D: and E:, then delete drive D:
Now you can expand drive C:

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