What Is the C Drive on a Computer?

Learn the difference between C and D drives

The C drive, or C: drive as it is often referred, is the main partition, often the main drive itself, which contains the Windows operating system the PC is running. When people refer to their computer's hard drive (or SSD), they are referring to what the operating system calls the C drive.

This is somewhat of a relic from the early days of Windows machines, and even dates back further to its DOS predecessor. In modern Windows PCs, the C drive has the main designation of Local Disk alongside the C lettering.

A PC with multiple partitions or drives, may have additional lettered drives, like D, E, F, G, and so on, though these can also be used to designate optical drives, or external storage solutions like thumb drives and portable hard drives.

Why Is It Called the C Drive?

The letter naming scheme for Windows still leans on its DOS legacy, where the A and B letterings were reserved for floppy disk drives since most computers at the time had a 3.5-inch floppy disk drive, and a 5.25-inch floppy drive (some didn't have a hard drive at all). The C drive has, since then, been reserved for the main operating system drive and its important system files even though floppy drives have slid into obsolescence.

What Is the Difference Between C and D Drives?

The C drive is the main partition for your Windows computer. In many cases, this will mean the C drive is also the main hard drive/SSD, but if you have a drive with multiple partitions, then it will only represent that particular portion of whatever hard drive or SSD partitioned for that purpose.

The Local Disk highlighted in the Windows file explorer.
The Local Disk (C:) highlighted in the Windows file explorer. The Windows icon on the icon of the drive indicates it's the boot drive.

The D drive will be a secondary hard drive, SSD, or partition of a drive. Depending on how your Windows PC was set up, it may also be used as a small partition on the main drive designated as System Reserved. This is sometimes set up when installing Windows to contain Boot Manager code and some startup files required for BitLocker drive encryption.

How Do I Find the C Drive On My Computer?

You can find the C drive from within the Windows file explorer by navigating to This PC. To do this, either search for This PC in the Windows search bar, or press Windows key+E and select This PC from the left-hand menu.

On older versions of Windows, you want to look for My Computer instead.

From the This PC window you should be able to see all of your Windows PC's drives, including the C drive.

What Can I Safely Delete From My C Drive?

Since the C drive is your main boot drive, you need to be a little more careful deleting anything from it, as there's a greater potential for you to do damage to your system.

As long as you don't remove any Windows specific files, it's not only safe, but also wise, to deleted old, unwanted files. Focus on removing unnecessary applications and games, clearing up your Downloads folder and Desktop, and see if that gets you the space you need.

You can also use disk cleanup applications to automate the process for you.

  • Why is my C drive full?

    Your computer's C drive, being its primary storage area, will likely fill up before the D. You can use a utility like Free Up Space or Disk Cleanup to find files that are safe to delete.

  • How do I move files from the C drive to the D drive?

    You may be able to move your files just by changing their locations in Properties. Right-click the folder to move (Documents, Music, Photos, etc.), and then select Properties. In the Location field, change the entry to D:\ [name of folder], and then click Apply and OK. Alternatively, open the folder you want to move, right-click an empty space, and go to Properties > Location > Target. Make the D drive the target, and your computer should move the folder over.

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