Choose the device file name of the third partition on the second sata hard drive.

Ever wish you could split your hard drive in two? Maybe you want to encrypt a portion of your drive for sensitive files, or perhaps you want to dual-boot Linux alongside Windows. It's actually easy to do, and all the necessary tools are built right into Windows.

This process is called partitioning your drive, and in fact, your drive is probably partitioned out of the box: the majority of the drive is occupied by the C: partition, but most PCs also have a small "Recovery" partition that can help repair your system if something goes wrong.

If you aren't using all the space on your C: drive, you can divide it into multiple partitions for other uses. Here's how to set it all up.

Should You Partition?

Partitioning your drive seems convenient, but it isn't always the ideal solution to your problem. If you want to encrypt files, for example, it may be easier to create a virtual disk with a program like VeraCrypt(Opens in a new window). However, by creating a partition, you can use Windows' built-in BitLocker to encrypt an entire partition and avoid using third-party software.

Similarly, partitioning allows you to allocate one portion of your drive to Windows itself, with another for all your music, videos, and other files, so they don't get deleted when you reinstall your operating system. This is convenient, but it can also cause as many problems as it solves—if you run out of space on one partition and have too much free space on the other.

If you don't have to partition your drive, consider the pros and cons before continuing. If you're dead set on partitioning—or you're doing something that requires partitioning, like dual-booting your computer—then read on.

Check for Free Space and Back Up Your PC

First, open Windows' File Explorer and make sure you have enough free space for the partition you want to create. Click on This PC in the sidebar and look at your C: drive—if it's almost full, you won't be able to create a new partition, and you'll either need to free up some space or buy a new hard drive.

If you have some free space, make sure it's enough—we can't tell you how much you'll need for what you're doing, but make sure you have enough to give you some breathing room for expansion.

Next, before partitioning your drive, back up your data. Messing with partitions always carries a small risk that you'll erase the wrong thing and lose some files, so don't start this process before backing up the drive. Here are some backup services we recommend.

Shrink the C: Drive

Click on the Start menu and type "partitions" and select Create and Format Hard Disk Partitions. You will be presented with a list of drives and their partitions, with a graphical view along the bottom.

Most computers will look something like the image above: a Recovery partition at the beginning, a small 100MB partition where boot information is stored, and your C: partition, which takes up the majority of the drive (note that this graphical representation is not to scale).

In order to create a new partition, you'll first have to shrink the C: partition. Right-click it and choose Shrink Volume. Windows will present you with a somewhat confusing window asking how much space, in megabytes, you want to free up (remember, 100,000 MB = 100 GB).

By default, it'll set your drive to shrink as much as Windows allows, but you can type in a lower number to free up less space. Make sure you have enough room to fit the files you expect to put on the second partition, plus a little extra. Click the Shrink button and let Windows to do its job.

Format the New Partition

Once you've shrunk your C: partition, you'll see a new block of Unallocated space at the end of your drive in Disk Management. Right-click on it and choose New Simple Volume to create your new partition. Click through the wizard, assigning it the drive letter, label, and format of your choice.

If you'll only be using Windows, you can choose NTFS as the format. You might want to choose exFAT if you plan to share data between other operating systems. If you're going to install macOS or Linux on that partition, it doesn't really matter how you format it, since the OS installer will likely re-format it anyway.

When you're done, you should see the new partition appear in File Explorer, and you can do whatever you want with it. Just remember that while Windows shows the partitions as multiple disks, they're still on one hard drive—so if the drive fails, all your partitions will fail. Keep both partitions backed up regularly so you don't lose data.

Unfortunately, partitioning a drive doesn't always go this smoothly. Maybe there are unmovable files near the end of the disk, and it won't let you shrink the existing partition. Or maybe your drive has accumulated a bunch of recovery partitions that Windows' Disk Management won't let you delete.

We can't go into detail on fixing every possible issue here, but if you hit a wall, you might want to try a third-party utility like MiniTool Partition Wizard(Opens in a new window). These programs tend to be a bit more powerful than Windows' built-in options, but certain features may cost money, and if you aren't careful, you can lose data in the process. As always, back up before you start messing with the drive, and you should be fine.

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