How to Create a Fourth Primary Partition in Windows 7 or Vista
Summary: First use Windows' Disk Management to create Unallocated space (RAW) on the hard disk. Next use Diskpart at a command Prompt to create the 4th Primary partition. Finally use Windows' Disk Management to Format, and allocate a drive letter to, the new Primary partition. A detailed explanation follows.
Note: If you have four Primary partitions, you cannot create any further (even Logical) partitions on that hard disk.
First create Unallocated space by Shrinking an existing volume on the Hard Disk
- Restart computer correctly (close all programs before you Restart computer).
- Open Disk Management in Windows 7/Vista (right-click Computer, select Manage, click Disk Management).
- Right-click the Primary partition to need to shrink in size, and click Shrink Volume
(you can shrink any Primary that's not Hidden in Windows Explorer).
- In Enter the amount of space to shrink in MB: enter enough for the new Primary.
- Click the Shrink button (it will take some time to complete!).
If Shrink does not give you sufficient Unallocated space, read Shrink the Windows 7 or Windows Vista Partition (new window) for instructions on how to complete this task successfully. Then return here.
Next use Diskpart at a Prompt to create the fourth Primary partition in the Unallocated space.
Warning: You must have created Unallocated space (RAW) on the selected hard disk before you continue.
- Backup important data - just in case!
- Right-click the Command Prompt shortcut and click Run as administrator
(Start > All Programs > Accessories > Command Prompt).
Click Yes if asked for User Account Control or enter your password.
- Type DISKPART at the Prompt and press Enter.
- Type LIST DISK at the Diskpart prompt and press Enter
- note the disk number for your new Unallocated space (Disk 0=1st hard disk, Disk 1=2nd, Disk 2=3rd).
- Type SELECT DISK Z, where Z is the number you just noted.
- Type CREATE PARTITION PRIMARY
- all the Unallocated space will be used for the new Primary.
- Type EXIT to exit Diskpart.
- Type EXIT to exit Command Prompt.
Finally Format the new Primary partition with Disk Management.
Your fourth Primary partition is now ready for use!
- Open Disk Management in Windows.
You'll see the new partition is a fourth Primary and is in a RAW state without a drive letter.
- Right-click that partition, select Change Drive Letter and Paths..., and Add a drive letter to it.
- Right-click that partition again and Format all of it (usually with the NTFS file system).