By Teresa / Last Updated August 26, 2019

Why you want to extend Windows 7 system partition?

“It is quite annoying when getting low disk space warning while working with my computer. It is like a threat that pushes me to delete files to free up disk space, or it will damage my system so that I cannot use it any more. Help please.”

Have you get such trouble on your Windows 7? Apparently, to extend Windows 7 boot partition mostly is to give sufficient space for operating system as well as installed applications. Deleting useless files or uninstalling programs fix this trouble temporarily yet same situation comes in the near future.

Another motivation for this behavior could be make full use of hard drive space. For example, you may want to extend C drive in Windows 7 to unallocated space or free space which is idle on the hard drive. Surely, you can have another intention for system partition extending in Windows 7. For instance, extend system partition size to make partition size reasonable. Well, let’s find out how to extend system partition in Windows 7.

How to extend Windows 7 system partition with built-in tools?

Windows 7 provides two disk partition managers that allow you to extend system partition in Windows 7 free, GUI Disk Management and CUI Diskpart. Let’s get to know them one by one.

Windows 7 Disk Management extend system partition

Disk Management in Windows 7 adds two new functions named “Shrink Volume” and “Extend Volume”. "Shrink Volume" only creates unallocated space behind the partition, and "Extend Volume" can only work when there is contiguous unallocated space. Make sure you have unallocated space next to system partition.

1. Open Disk Management [Computer > Manage > Storage] and right click Windows 7 system partition. Select “Extend Volume” from the given menu.

Extend Volume C

2. Follow the Extend Volume Wizard and click “Next” several times to complete.

Extend Volume Wizard

Nevertheless, there are some limits you may want to know. To extend C drive to non-adjacent space, you need to delete the partition between system drive and free space. Otherwise, you’ll get into Windows 7 extend system partition grayed out trouble.

Diskpart: extend system partition in Windows 7

Another helpful tool is Diskpart.exe in Windows 7. It is more advanced operating method with which operations cannot be returned. Therefore, use this program with caution.

1. Open Run [press Windows key and R key simultaneously] and type “diskpart” and press Enter. Run as administrator.

Run diskpart

2. Input commands below in order and each command has an “Enter” followed by.

  • list volume

  • select volume n [n is the number of your system C drive]

  • extend

  • exit

Diskpart Extend System Partition

Go check in Disk Management and you’ll find system partition has been extended. However, when the unallocated space or free space does not adjacent to system drive, Diskpart cannot extend system drive in Windows 7, and it will give you error message saying: There is not enough usable free space on specified disk(s) to extend the volume.

In that case, it is a good idea to turn to professional and reliable partition manager. AOMEI Partition Assistant Professional allows you to extend C drive in Windows 7 without formatting, both 32-bit and 64-bit. You can extend NTFS boot drive with ease and without data loss. Just to be on the safe side, backup important data beforehand.

Expand Windows 7 system partition via AOMEI Partition Assistant

Step1. Installl and run this software. Clearly, behind G drive there has a large size of unallocated space. Right click C drive and choose "Merge Partitions".

Merge Partition

Step2. In the following window, check system drive and all unallocated space and click "OK".

Add Unallocated Space To C Drive

Step3. Remember to click "Apply" to commit the task.

Apply Merge


  • If there is no free space or unallocated space on your hard drive, to extend system drive you can Allocate Free Space from other redundant partitions.

  • To avoid low disk space warning appears on system partition, you can also install applications and third-party software separately to system drive, data partition for example.

In summary, it is not so hard to extend Windows 7 system partition using either Disk Management or AOMEI Partition Assistant. However, for the safety of your data, it is suggested to use the second method.

Apart from extending Windows system partition in Windows 7, this method also applies to Windows 10/8/XP/Vista. AOMEI Partition Assistant is all-around software, for example, you can shrink C drive beyond half with it when C drive is too large.