What Is C Drive in Computer? [Differences with D: Drive]

By John Adebimitan

The storage units of a computer have letters associated with them that designate an access path. The C drive, which is accessible through your file explorer, is found in almost all computers. Sometimes supported by a D or E drive, the C drive is the main storage system of your computer. 

But many don’t know what the role of the C drive in computer is, how important its function is, and to what extent it can be maneuvered while trying to optimize your computer storage space.

Not to worry, in this article, I’ll be talking in-depth about what the C drive in computer is, what its function is in relation to the secondary D drive and how you can best manage and troubleshoot common issues in a computer’s C or complete hard drive. Let’s get to it!

What Is C Drive in Computer?

The C: drive in a computer is a part of the hard disk that stores the operating system, which is the computer program that manages other applications. 

The C: drive in a computer can comprise the entire storage space on a hard drive, a part, or a logical partition defined on it.

A physical hard-disk drive can be configured and treated by software as multiple drives, each with its DOS-era alphabet name. However, the C: drive, whether physical or logical, always stores operating system software.

Where did the “C” drive come from?

The “C” drive and the letter naming scheme for computer drives come from the days of disk operating systems (DOS), also known as Microsoft Disk Operating Systems or MS-DOS.

In the old days when computers “booted” or loaded their operating systems from floppy disks (software), the bootable floppy disk drive (hardware) was named “A” drive. If the system had two floppy drives, the second was named drive “B”.

When the hard drive was added, it was named C to keep it in line with established DOS procedures. A second hard drive, a logical or physical partition, would be named drive D.

Functions of a C drive in computer

The main function of the C: drive in computer is to provide a permanent storage medium for the operating system and other files/programs needed to “boot” the machine. Hard drives can reliably store this data even if powered off or physically removed from the computer.

The C drive in computer could also be the storage medium for application software and device drivers. It is therefore essential for a properly functioning computer.

Also, the C: drive is the default drive, and it is where the operating system should find certain files during system startup. Moreover, C: drive stores data in an orderly manner, and keeps track of where it is.

Differences Between C and D Drives

At the risk of paraphrasing a famous humorist, I would say that the difference between C: and D: drives are of the same nature as the difference between the two legs of a duck! They are identical.

So, first of all, the drive letter is not assigned to a disk but to a partition. This means that your hard disk is “cut” into 2 parts: the main part which is the C: houses the OS which is Windows and the software present on it.

Meanwhile, the Data part (D:) which is usually empty on a new PC is used to store your downloaded and installed data! Basically, on the C: you install your software, and on the D: part, you store your data.

But by leaving the C: only for Windows and software, the computer will gain a lot in booting and operating speed and access to data.

Is C Drive an SSD?

In some newer computers, the SSD is also the C drive. The SSD (Solid State Drive) is a storage medium that uses memory chips called flash memory chips.

It is replacing the Hard Disk Drive (HDD) in some computer models but some brands are wise enough to combine both as they have individual advantages. So, in hybrid computers (that is, with both types of drives), the C: drive is usually the SSD while the D: drive is usually the HDD.

But in computers with only an SSD storage, they only have C drives, so to say, just like some old HDD computers have just the C drives without a D drive, except you do a partitioning.

To be clear, the SSD fulfills the same function as a hard disk except that it is devoid of any mechanical part. By using memory chips, the SSD has several decisive advantages over a traditional hard drive.

The most obvious is performance: with reduced access times and higher throughputs, the SSD allows reactivity and instantaneousness unknown to hard disks.

Where Is the C drive on Windows 10?

The C drive is found where you can find it in previous versions of Windows OS computers.

What Is C Drive in Computer [Differences with D: Drive]

Click on your Windows key.

Then type “Windows Explorer”.

As Explorer opens, you’ll find by the left part of the window an icon named “Local Disk (C)”. When you double-click on this icon, you will be able to see the contents of the “C” drive.

How to Partition a C Drive on a New PC?

With a Windows PC, you can partition a PC using the Windows Disk Management tool, the Diskpart utility, and third-party programs outside of Windows.

As these operations are quite technical – and therefore delicate, not to say dangerous – they are not carried out directly in Windows Explorer, but with specific tools.

Partitioning with Windows Disk Management  

The first, and simplest process which I’m going to explain is the one done with the Windows Disk Management tool.

  1. Access this tool by clicking on the Start menu.
  2. Right-click on This PC and click on Manage
  3. Click on the C disk from which you want to partition
  4. Double-click on the Unpartitioned space which can be named System Reserved and located in the bottom pane.
  5. Then click on New Simple Volume.
  6. Choose the size you want, click next, and that’s it.

Partitioning with DiskPart

The second, much more complex, is the utility DiskPart, from Microsoft. Much more powerful, it can perform more sophisticated and delicate operations, even on disks that Windows does not recognize.

But everything is done in an old-fashioned interface, in text mode, using command prompts that are typed.

Partitioning with third-party programs

The third solution consists in turning to specialized utilities which are not offered by Microsoft but by third-party publishers.

There are many, some free, like EaseUS Partition Master Free, Partition Manager, or the AOMEI Partition Assistant Standard.

Some are also paid. These include tools like Partition Find & Mount, Paragon Partition Manager, or O&O Partition Manager Pro.

A Step by Step Guide to Cleaning Up Your Hard Drive

Your hard drive or SSD is full, your computer is slow and you need more storage space on your PC? I’ll give you a few tips on how to clean up temporary data, unnecessary programs, and more in a Windows computer so that the PC can run faster again.

Step 1: Analyze memory

How much space is still free on the individual hard drives and partitions? How much is occupied by apps, temporary files, music, or pictures? You can find out in the Windows settings.

  1. Press the [Windows] and [i] keys.
  2. Go to System and Storage. Windows will display the used and free memory on all connected drives.
  3. Clicking on a storage volume opens a new window with detailed information about the different data types.
  4. Click on Temporary files and you can remove the recycle bin, thumbnails, and other unnecessary data.

Step 2: Identify storage hogs

Which files eat up the most portion of your hard drive? You can easily find this out in Windows Explorer.

  1. Select a hard drive or a folder by clicking on it.
  2. Then enter the size (for example, >100MB) in the search field at the top right and confirm with [Enter]. Explorer will show all files larger than 100 MB.
What Is C Drive in Computer [Differences with D: Drive]
  • From here, you can see large files that may not be necessary and delete them.

Step 3: Delete duplicate files

If you have a lot of pictures and MP3s on your hard drive, you may lose track and some files may be duplicated or tripled.

The Duplicate Cleaner detects such duplicates. It analyzes folders or entire drives and shows duplicates. If desired, the program can delete the duplicate data immediately.

Step 4: Uninstall programs and apps

If space on the hard drive is tight, you may delete unnecessary programs. This works better with the Iobit Uninstaller than with the Windows on-board tools.

It sorts software according to categories such as “rarely used” and “extensive”. When uninstalling, the free uninstaller also cleans up leftover entries in the registry. Iobit can also remove toolbars and browser plugins.

Step 5: Clean up file history

File history can take up a lot of storage space over time. You should therefore regularly clear out the file history.

  1. Call up the settings with the [Windows] and [i] keys.
  2. Enter Control Panel in the search field. 
  3. In the next window, click File History and then click Advanced Settings on the left tab. 
  4. Now click on Purge versions and choose which data will be deleted.

Step 6: Delete Windows.old folders 

Old Windows versions and shadow copies are stored in their folder in the system directory. Use Disk Cleanup to delete the windows. old folder.

  1. On the Windows search bar, type Clean Up
  2. Then click on the button that reads Clean Up System Files
  3. Select the C drive if you have multiple drives
  4. Mark Previous Windows Installation
  5. Click on OK to delete

Step 7: Clean up with CCleaner

  1. CCleaner removes data garbage of all kinds. To use it to clean up the hard drive, download, install and start the program.
  2. Click on Cleaner and check all data that should be deleted.
  3. Select the Analyze button and then start CCleaner. 

You can also use the program to clean up the registry, uninstall software, securely delete files and find duplicates.

Step 8: Back up data in the cloud

Do you have large music, video, or photo collections and you are running out of storage space on your computer? Outsource the data – either on an external hard drive or in the cloud, for example with Google Drive, OneDrive, or Dropbox.

The advantage here is that you can also access your data from other devices, for example from a smartphone or tablet.

How to Solve “C Drive is Full” Issue in Windows 10 – Working Tips

The “C Drive is Full” is an error message that pops up when the C drive in computer is running out of space. To solve this issue, here are some working tips:

  1. Extend the C drive space with an external partitioning program like the EaseUS Partition Master
  2. Run disk cleanup as shown earlier
  3. Delete temporary folders on the C drive
  4. Regularly empty your Recycle Bin
  5. Clear large files that are not needed
  6. Deled Windows.os folders
  7. You can also backup C drive data and upgrade to a larger drive
  8. Transfer large files on the C drive to an external drive

How to Move Files from a C Drive to Another Drive to Free up Space?

By default, Windows stores the system’s data on the C partition. However, you can still find personal files or transferred files in the C drive. For more comfort, it is recommended to move your personal and computer data on the C drive to another partition, another disk, or another computer on the network.

Here are the personal folders created by default by Windows for a user in a C drive in computer: Contacts, Desktop, Downloads, Documents, Favorites, Pictures, Links, Music, Saved Games, Searches, and Videos.

What Is C Drive in Computer [Differences with D: Drive]

To illustrate this tutorial, I will use a computer equipped with a single disk that has been partitioned and divided into two parts: on one side, I have the partitions specific to Windows; and on the other, a DATA partition where you can store the user’s files.

Currently, we, therefore, have two partitions: OS (C:) and DATA (E:).

You’ll need to change the location of the User folder where the Documents, Pictures, etc. folders are stored. Instead of the Windows partition (“Local Disk (C:)”), they will be stored on the DATA partition (“System Reserved (E:)”).

While thinking of freeing space by moving the files on your C drive, have it at the back of your mind that you can only move Users files. To move a user’s home folders to another drive, follow these instructions:

  1. Open File Explorer
  2. Go to the new location (System Reserved (E:)) where you want to store the user’s folders.
  3. Create a “Users” folder, then inside another folder with the user’s name.
  4. In the “[Username]” folder, create the personal folders you want to move from the default location. You can choose to move the following folders: Documents, Music, Videos, Pictures, Downloads, Desktop, Favorites, Contacts, etc.
What Is C Drive in Computer [Differences with D: Drive]
  • Navigate to the user’s home directory by entering “%USERPROFILE%” without the inverted commas in the address bar.
What Is C Drive in Computer [Differences with D: Drive]
  • Right-click on a personal folder to move then select Properties.
What Is C Drive in Computer [Differences with D: Drive]
  • Go to the Location tab and click on Move.
What Is C Drive in Computer [Differences with D: Drive]
  • Choose the previously created folder in the new location and click Select Folder.
What Is C Drive in Computer [Differences with D: Drive]
  • Click OK then confirm the move of the folder.
What Is C Drive in Computer [Differences with D: Drive]
  1. Here, all the files and folders present in the Documents folder will be moved from the Windows partition (“C:”) to the DATA partition [System Reserved (E:)]
  2. Repeat the process for any other home directory folders you want to move.
  3. To verify that the folders have been moved, go to the new location (the DATA (E:) partition). The folders created initially had the default folder icon; they should now have the icon corresponding to the type of files they are supposed to include.

Congratulations! You have moved a user’s folders (Documents, Pictures, Videos, etc) to another partition, which can be your D or E drive.

Warning! You can only move the files in Users in your C drive to the D or E drive, or another drive you have. Never try moving important files such as Intel, Program, or Windows folder from the C drive. The C drive in computer is their permanent home.

Read also: Why Is My Download Speed So Slow on PC?


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