Can't Extend Primary Volume Size in Windows 7/8/10-How to Solve?

June 1, 2017

Can’t extend primary volume size with unallocated space in Windows 7/8/10? AOMEI Partition Assistant will give you the best 2 ways to extend C drive safely in this article.

Why you can’t extend primary volume size in Windows 7/8/10?

As we all known, Windows primary partition (also named system partition) contains system files and other installed applications, configured data, page files, etc. Typically, the file system on primary partition is NTFS format and the C drive is labeled system primary partition. With the daily use of computer, you will find the Windows system partition running out of space, and the program installed on this partition running slowly. Or you will get a low disk space warning after upgrading Windows operating system to a latest version of Windows, you could delete Windows.old folder to free up space for your hard disk, and extend system partition if you want more storage. On these conditions, you may find the extend partition is greyed out and can’t extend primary volume size in Windows 7/8/10.

Why you can’t extend primary C partition? There are some reasons you can refer to:

1. If you installed the Windows operating system before Windows Vista, extend volume is not supported by Disk Management.

2. There is no contiguous unallocated space on your hard disk, or the contiguous unallocated space is located before the Windows primary system partition.

3. The primary partition you want to extend is formatted with FAT file system.

Now, to extend primary C partition size effectively, we will introduce you the best disk partitioning manager-AOMEI Partition Assistant Professional, which is applied to Windows XP, Vista, 7, 8, 8.1, 10. It allows you extend C drive with unallocated space, no matter where the unallocated space is located on that disk.

How to extend primary partition size safely?

AOMEI Partition Assistant Professional will give you the best two strategies to solve can’t extend primary partition problem: Extend Partition Wizard, and Resize Partition.

Here we are going to show you the details about extend primary volume size in Windows 7/8/10 with Extend Partition Wizard:

Before extending, make sure you have an unallocated space on your hard disk, delete a partition to generate one if you do not have the space. Please close all applications on system partition that you want to extend.

1. Above all, you have to download AOMEI Partition Assistant Professional, launch it to main interface after installation.

2. In order to solve can’t extend primary volume size, click Extend Partition Wizard under Wizards column.

Extend Partition Wizard

3. Tick Extend system partition, hit Next>Next.

Extend System Partition

4. Drag the slide rightwards to extend primary C volume to proper location, press Next.

Partition New Size

5. Press Proceed to extend system C partition.


A few seconds later, the problem that can’t extend system partition will be resolved. Besides, you can try Resize Partition feature to extend C volume.

Resize Partition

Apart from extend partition with unallocated space, you can allocate free space from other partition to primary volume if you don’t have an unallocated space. In addition, AOMEI Partition Assistant Professional offers you to convert GPT to MBR without losing data, merge partitions, migrate OS to SSD, and many advanced functions. For basic users, it gives you the Standard edition to enjoy.