Easiest Way to Extend System Partition in Windows 7 without Formatting

Learn how to extend Windows 7 system partition using Disk Management and free AOMEI Partition Assistant when the Extend Volume greyed out.


By Lucas / Updated on May 12, 2023

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

Another motivation for this behavior could be making full use of hard drive space. For example, you may want to extend C drive in Windows 7 with unallocated space or free space on the system 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 free 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.

Method 1. 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.

Method 2. Extend system partition in Windows 7 via DiskPart

Another helpful tool is Diskpart.exe in Windows 7. It is a 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]



Diskpart Extend System Partition

Go check in Disk Management and you’ll find system partition has been extended. However, same as Disk Management, when the unallocated space or free space is 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.

Expand Windows 7 system partition via free partition software

When there is no adjacent unallocated space behind the system drive and you don’t want to delete any other partition, either, you can turn to the free manager software: AOMEI Partition Assistant Standard. It allows you to extend C drive in Windows 7 without formatting, both 32-bit and 64-bit. Its "Merge Partition" function can directly merge non-adjacent unallocated space into C drive or other partitions. Just to be on the safe side, backup important data beforehand. Then you can download the freeware and see how it extend Win7 boot drive.

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Step 1. Installl and run this software. Clearly, behind D drive there has a large size of unallocated space. Right click C drive and choose “Advanced” and select “Merge Partition”.


Step 2. In the following window, check system drive and all unallocated space and click "OK".


Step 3. Remember to click "Apply" to commit the task.


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

In summary

It is not so hard to extend Windows 7 system partition using either Disk Management or DiskPart. However, for the safety of your data, it is recommended to use the recommended freeware. 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 move partition to make unallocated space adjacent to the target partition you wish to extend, shrink C drive beyond half with it when C drive is too large, clone partition and more.

Lucas · Staff Editor
I prefer peaceful and quiet life during vacation,but sometimes I watch football match if my favorite club performs brilliantly in that season. And I love reading, painting and calligraphy, thus I send my friends festival handwriting cards every year.