By Teresa / Last Updated June 1, 2020

Overview of partition

It’s necessary to have a basic understanding of partition before learning how to partition C drive in Windows 10/8/7. Partitions are the regions that separate one physical hard drive into multiple volumes. Disk partitioning is the creation of one or more regions on a hard disk or other secondary storage and is the first step of a newly manufactured disk, before any files and directories have been created. There are many benefits of multiple partitions on your hard drive and some are listed as follows:

▶ Separation of the operating system (OS) and program files from user files. In this case, you can image, backup or clone only operating system and installed programs instead of the entire disk, which will save you lots of time.
▶ Partition hard drive for dual boot. This allows you to have more than one operating system on a single computer. For instance, you can install Windows 7 and XP in different partitions of the same HDD, and you can choose to boot whichever operating system you want to at power-up.
▶ Protecting or isolating files. This allows you to recover a corrupted file system or operating system installation easily because one partition is corrupted, other file systems may not be affected.

When need to partition C drive?

Typically, you may encounter two different situations when considering partition C drive.

Situation 1. Most PCs come from the factory with one single partition on their hard drive, which means it shows up as one drive (C drive, mostly) in the computer window. Under such circumstances, you can shrink C drive and create a new partition with that redundant space by using Disk Management. Backup data in the first place. Although this partition operation won’t cause data loss, you cannot stake for that anyway.

Situation 2. The new PC was well-partitioned by the seller when you bought it. But you find the system partition (C drive) is far away from large enough for you to run the system since you have received “Low Space” warning from the computer now and then. Worse still, you cannot fix this out using Disk Management, because it works only if there is unallocated space right behind C drive, otherwise, you will see “Extend Volume” is grayed out like the first screenshot above.

How to partition C drive in Windows 10/8/7?

In two different conditions, you need to take corresponding ways to partition C drive.

Solutions for Situation 1: Partition C drive for more partitions

Solutions for Situation 2: Extned C drive without losing data

Partition your C drive for more partitions

In Situation 1, you need to shrink C drive and then create a new partition with the unallocated space. To complete this task, you can employ Windows built-in Disk Management.

Firstly, access Disk Management with "Start”-> “Control Panel”->“Administrative Tools”-> “Computer Management”-> “Disk Management”. Then you will see the first window below.

Then, right-click C drive and select “Shrink Volume”, you can type in the amount of space you want to shrink the disk by (the second window). By the way, Windows 7 requires more than 16 GB of available space, if you want to install dual OS. After you shrank successfully, you will see one unallocated space after C drive, and then right-click that unallocated space and select “New Simple Volume” to edit the details of the partition following the wizard.

Disk Management

Snap3 Disk Management

Or you can split C drive into two partitions easily and quickly via third-party partition manager, AOMEI Partition Assistant Professional. Here are the detailed steps:

Download Demo Win 10/8.1/8/7/XP
Secure Download

Step 1. Install and run the software. Right-click the C drive and select “Split Partition”.

C Drive Split

Step 2. Type in the amount of new partition or just drag the circle in the middle to decide the size.

Resize New Partition

Step 3. Click “Apply” and "Proceed" after your confirmation.

Apply Split C Drive

Yes, you have got one new partition now. You can create more partitions by repeat above steps, but pay attention that one MBR disk can only contain up to four primary partitions or three primary partitions and one extend partition which may include unlimited logical partitions.

Extend C drive withotu losing data

In Situation 2, you need to extend partition C because the C: drive is running out of space, which may slow down your program's running speed. If there is a contiguous unallocated space behind C drive, you can extend C drive with the unallocated space in Disk Management.

If you do not have unallocated space here, you can resize the partition (D:, E: F:, etc) to get an unallocated space but the unallocated space won't be adjacent with C drive and you'll still be unable to extend C drive in Disk Management. In such a case, you can use the software aforementioned, AOMEI Partition Assistant Professional. It enables you to add non-contiguous unallocated space into C drive and allocate free space from a partition with enough capacity to partition C.

Now, let's see how it extend C drive with non-adjacent unallocated space on the same hard drive. You can download its demo version to have a try!

Download Demo Win 10/8.1/8/7/XP
Secure Download

Step 1. Open AOMEI Partition Assistant Professional. To extend C: drive, here you can merge C: drive with unallocated space. Right-click C drive, choose Merge Partitions.

Merge Partitions

Step 2. here you can choose to merge C: drive with the unallocated space.

Check Unallocated Space

Step 3. the size of partition C is 175.26 GB now, click “Apply” to execute these operations.

Apply Merge Partitions


Now, you are already known how to partition C drive without losing data under different situations. In fact, apart from partition C drive, AOMEI Partition Assistant Professional owns many other functions, such as migrate OS from GPT disk to a GPT/MBR SSD or disk, convert system disk between MBR & GPT partition styles, change the serial number, change partition type ID, etc.