By Emily / Last Updated October 29, 2019

"Can I extend C drive without formatting?"

“I have 150 GB on my C drive, but now it is almost full, due to which my Windows 10 computer is slowing down now. So I want to add more space into it to extend the space of C drive. But the problem is that all my disk space has been divided into partitions.

So, does anyone know how to extend C drive in Windows 10 without formatting or deleting a second partition on the disk? Or can I move some unused space from other partitions such as D, E or F to my C drive without deleting or formatting them? Thanks!”

How to increase C drive space without formatting in Windows 10/8/7?

To extend C drive without formatting in Windows PC, you can use the Windows native Disk Management tool as well as turn to a third-party disk manager. Here we will introduce how to enlarge C drive via those two tools.

1. Extend C drive without format via Disk Management

Many users are searching on Google: how to extend C drive in Windows 10 without any software. In this case, Disk Management would be a great choice, which comes with “Extend Volume” and “Shrink Volume” features. They are useful for increasing or decreasing partition size.

However, sometimes you will find the Extend Volume greyed out when you right click the volume you plan to extend and try to choose this option. Why? That’s because Disk Management has below limitations:

  • It only can extend a primary partition when there is an unallocated space on its right side.

  • The partition you want to extend should be in the NTFS or RAW file system, otherwise, the “Extend Volume” will be greyed out as well.

  • You can get unallocated space by shrinking a partition, but it will be located after the shrunken partition and cannot be moved to any other locations.

On the whole, to extend C drive without formatting or deleting the second partition in Disk Management, there must be a contiguous unallocated space on the right side of C partition. The same limitations are also applicable to extend C drive without formatting using CMD.

2. Increase C drive space without format via AOMEI Partition Assistant

In order to evade the restrictions of Disk Management and enlarge C drive memory without formatting or deleting partition, it is better to use a third-party disk manager like AOMEI Partition Assistant Professional. It can perform many disk management tasks that cannot be done by Windows built-in tools, including:

✌Move partition: move partition to another location on the same disk as long as unallocated space is on its either right or left side. This way indirectly moves the unallocated space.
Merge partition: merge two adjacent partitions into one, or merge unallocated space (on the same disk) into another existing partition.
✌Wipe partition: completely wipe all data from one specific partition and reduce the data recovery chance.
✌Copy partition: clone partition to another drive or hard disk, to achieve the goal of transferring mass data from partition to partition.

As for how to extend C drive without formatting in Windows 10/8/7, you can try its “Allocate Free Space” and “Merge Partition” functions, depending on whether there is unallocated space on the disk.

Before proceeding, you can download the Pro Demo to have a try.

Method 1. Allocate free space-extend C drive without unallocated space

This method is able to assign unused space from one partition to C drive, proper for the user case mentioned in the first part. If you are also experiencing that, do as following.

1. Install and run AOMEI Partition Assistant Professional. Right-click the D drive, which has free space, and choose “Allocate Free Space”.

Allocate Free Space

2. In this window, you can decide to allocate how much free space from D to C drive. Then click "OK".

Allocate From D To C

3. Hit on "Apply" to execute the pending operation.

Apply Allocate Free Space

Besides, you can also try “Extend Partition Wizard” to extend NTFS system partition without rebooting computer.

Method 2. Merge partition-extend C drive with unallocated space (not next to C drive)

With this method, you can merge unallocated space into C drive no matter whether it is on the right side of the C drive or not.

1. Right-click C drive and choose “Merge Partitions”.

Merge Partition

2. In this window, tick the unallocated space and click “OK”.

Add Unallocated Space To C Drive

3. Back to the main interface, click “Apply” to commit the pending operation.

Apply Merge

Final Words

Now you should get a comprehensive understanding of how to extend C drive in Windows 10 without formatting or deleting partitions. If you want to make extending system partition as easily as possible, AOMEI Partition Assistant Professional is worth your trying.

Apart from resizing partitions, it also has other functions such as cloning MBR disk to GPT, migrating OS to SSD, recovering deleted partitions, converting MBR and GPT without deleting partitions.

If you are planning to extend system partition in Windows Server and enjoy such amazing functions on Windows Server computer, AOMEI Partition Assistant Server can satisfy your requirements.