Can I Create a Partition From the Hard Drive Where I Installed the OS

My hard drive is 512 GB in total. I want to have around 100GB in one partition for my OS and a 2nd partition for storing files. How should I do it? Any suggestions would be appreciated.

Yes, you can. A reliable partition tool is what you need to create a partition from the hard drive where you installed the OS. This post contains professional partition software EaseUS Partition Master and a Windows built-in tool Disk Management.

Solution 1. EaseUS Partition Master

With easy steps and powerful features, EaseUS Partition Master enables you to deal with many partition tasks with ease. You may need to create some if you haven't unallocated space on the target drive.

Refer to the full guide to creating a partition with EaseUS Partition Master:

Step 1. Create unallocated space.

  • Right-click the partition that has a lot of free space and click "Resize/Move."
  • Shrink the partition by dragging one of the partition ends. Click "OK" to go on.

Step 2. Enter Partition Manager and right-click the unallocated space to click "Create."

Step 3. Confirm the advanced settings, including partition number(two), size(100 GB and 412 GB), drive letter, partition label, and file system. Click "OK."

Step 4. Select "Execute 1 Task" and "Apply" to create a new partition on your MBR drive.

Solution 2. Disk Management

The second way is to split the hard drive with Disk Management, which also needs to create unallocated space for new partitions. Here is the detailed procedure:

Note: Disk partitioning may cause data loss, so back up the whole target HDD before starting.

Step 1. Right-click on This PC > Enter "Manage" > Click Device Manager and open "Disk Management" as an administrator.

Step 2. Find the hard drive on which you want to create partitions and right-click on the free-space dominant partition to choose "Shrink Volume." Change the partition size and tap on "Shrink" to confirm.

Step 3. Right-click on unallocated space, click "New Simple Volume," and select "Next" to continue. 

Step 4. Set the size as 100 GB and 412 GB, drive letter, and file system of the two new partitions, and click "Finish" to end.