How to Unallocate a Drive Volume in Windows
When you unallocate a volume in the Disk Management console, you’re not only removing it from the storage media roster — you’re also deleting all its data. In fact, the command that’s used isn’t unallocate or de-allocate but, rather, delete. After a volume is deleted, it’s gone. Its status in the Disk Management console window returns to Unallocated.
By unallocating a volume, you destroy all data on that drive. You have no way to recover folders or files from a drive that’s been unallocated. Proceed with these steps at your own peril:
Open the Disk Management console window.
Open the Control Panel.
Open the Administrative Tools window.
In Windows 7, choose System and Security and then Administrative Tools.
In Windows Vista, choose System and Maintenance and then Administrative Tools.
In Windows XP, open the Administrative Tools icon.
Open the Computer Management icon.
In Vista, click Continue or type the administrator’s password.
Choose Disk Management.
Right-click the volume you want to unallocate.
The volume cannot be the system volume, from which Windows was started, or any volume that is in use or accessing the drive or that has files open or programs running.
Choose the Delete Volume or Delete command from the shortcut menu.
Despite the command name, the physical hard drive isn’t deleted. Instead, the command merely removes the reference to the disk drive partition from the operating system’s view and unlinks the partition from the drive’s master boot record.
If prompted, click the Yes button in the suitable warning dialog box.
Another warning may appear if Windows believes the volume to still be in use.
If you’re certain that the volume isn’t in use, click the Yes button to de-allocate (delete) the volume.
That’s it. The volume is instantly deleted, and its status in the Disk Management console window is demoted to unallocated.
The unallocated portion (all or a part) of a disk drive cannot be used by Windows. You can do three things with that chunk of disk space:
Reallocate the space. You can reallocate the partition by setting it up as another drive in Windows.
Extend the volume. It’s possible to use unallocated space on an existing hard drive to increase the existing drive’s capacity.
Use the partition for another operating system. By not doing anything, you keep the unused space available for another operating system, such as Linux. The installation program for this operating system prepares the volume for use.
You can always choose to do nothing, of course. In fact, some unallocated chunks of disk space may already be shown in the Disk Management console for your PC. That’s fine. Sometimes, a chunk of disk is too small to use for anything, anyway. If that’s the case, though, consider extending the volume.