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C Drive Full? Here are 5 Proven Fixes For a Full C Drive

February 7, 2024

c drive full

We've all been there -- the C drive full warning that seems to pop up at the worst times, slowing down our computers and hindering productivity. 

This error message is a common issue that many computer users may encounter. When the C drive, the primary storage drive on most computers, runs out of space, it can cause your computer to become less responsive. This error limits your ability to save new files and prevents you from installing new applications or software updates.

In this guide, you’ll get simple steps and effective techniques to free up valuable disk space and restore PC performance.

What are the common causes for the C drive full error?

Before trying out solutions, it's good to know what caused your C drive to fill up, so you are empowered to stop it from happening again. 

Some everyday activities store data files over time without you even realizing it. These hidden files gradually eat up lots of space, slowly choking your drive.

Identifying these types of files can help you clean up and manage your files smarter.

Temp files

Various temporary files, commonly referred to as temp files, are created by the operating system and applications, which can accumulate over time.

For example, when you browse the internet, your browser creates temporary internet files, including caches, cookies, and browsing history. These files are stored on the C drive, contributing to the C drive filling up faster.

Large file downloads or application installs

Downloading large files, such as high-definition videos or installing software applications, can consume significant storage space on the C drive.

System updates

When your operating system releases updates, such as Windows updates, the installation files are stored in the C drive by default.

If these files are not promptly removed after the update is completed, they result in the C drive full error. System updates, while crucial for maintaining security and performance, occupy a significant portion of the C drive.

System updates take a significant portion of the C drive.

Source: EaseUS

Regularly clearing unnecessary files is essential to prevent this issue. But there is no reason as it is easily fixable by implementing the following techniques.

Tip: Backing up your vital data before making changes is crucial to prevent data loss or file corruption.

Tip 1. Extend the C drive via disk management

Extending the C drive is the most straightforward way to resolve the C drive full error.

To do this, you will need a disk management tool.

Disk management’s Extend Volume feature allows users to extend the C drive effectively. It can work when there is unallocated space behind the C drive. However, you may find that the Extend Volume option is grayed out if there is no adjacent free space.

In this case, you can turn to reliable third-party software.

Now, let's learn the step-by-step instructions for extending the C drive via disk management:

Step 1. Press the “Windows + R” keys to launch the Run dialog

Step 2. Then, type “diskmgmt.msc” in the box and hit “Enter” to open disk management

Step 3. Select the “Extend Volume” option after right-clicking on the C drive

Extending C drive via disk management

Source: EaseUS

Step 4. Set the C drive to extend to available space in Extend Volume Wizard and click “Next” to continue

Step 5. Click “Finish” to close the process

Tip 2. Run C disk cleanup to remove temporary files

Over time, the C drive of your computer can accumulate various types of temporary files that take up precious disk space. Here are some of the main temporary files.

Temporary internet files

These include browser caches, cookies, and browsing history files that build up as you surf the web.

Browsers like Chrome, Firefox, and Edge store these files locally on your C drive. Over time, these temporary internet files can accumulate and occupy significant space in your drive.

Temporary Windows files

Windows generates temporary files for various functions like updating apps, loading programs, managing memory, and more. Some of these are software distribution folders, memory dump files, Windows update install files, and thumbnail cache files.

Software installer files

When you install new programs on your system, the .msi or .exe setup files are often left behind after installation. These redundant installer files take up drive space.

System error logs

Windows keeps Event Viewer logs detailing system errors and application crashes. These log files continuously grow over time.

Downloaded program files

The original downloaded setup files often remain on your system when you download software programs or resources like PDFs. Over time, you can accumulate gigabytes of setup files you no longer need.

These files can slow down your computer's performance and affect its efficiency. However, Windows provides a built-in disk cleanup tool to resolve this problem effectively.

The disk cleanup tool scans your computer's hard drive and identifies temporary and junk files that are no longer needed. Once the tool has identified these files, it can seamlessly delete them to free up disk space and improve your computer's performance.

Here is how to use disk cleanup to clear useless files in Windows 10 or 11:

Step 1. In the taskbar Search box, type “Disk Cleanup” to locate it in the results list (or you can launch File Explorer - right-click the local C drive to find the Disk Cleanup tab after entering Properties > General)

Step 2. Check the files you want to remove and click “OK”

Disk cleanup for Windows

Source: EaseUS

Step 3. Click ”Delete files” in the pop-up window to confirm this operation

To free up more disk space, choose “Clean up system files”

Tip 3. Uninstall unnecessary programs from the C drive

If you know what is a C drive, you are familiar with the fact that most applications and programs will be installed on the C drive by default. Thus, another efficient way to clean up the C drive is to uninstall unnecessary programs.

It's necessary to identify if the program should be removed or retained before you uninstall it. 

First, select the program you want to delete or that hasn't been used for a long time, and perform a quick search online to determine if it's safe to uninstall. Then, find if the target program has dependencies on other software or libraries using dependency checkers like Dependency Walker (Windows). 

Lastly, don't forget to back up the crucial data associated with this program.

Follow the steps below to learn how to uninstall unwanted applications and programs in Windows 10 or 11:

Step 1. Click the Start icon to launch Windows Settings, then select “Apps > Apps & features"

Step 2. Locate the programs you want to delete and choose it directly, or click the three-dot icon to hit "Uninstall"

Uninstall unwanted apps and programs on Windows

Source: EaseUS

Some programs can't be uninstalled from Windows Settings. You can try to uninstall them in the Control Panel:

Step 1. In the Search box on the taskbar, enter the Control Panel and open it

Step 2. Select "Uninstall a program" under the "Programs" tab

Step 3. Choose the program you want to remove and click the "Uninstall" button at the top of the list

Step 4: Then, follow the on-screen instructions to finish the process

Uninstalling unwanted programs using the control panel

Source: EaseUS

Tip 4. Transfer large games or apps from the C drive to another drive

If you still want to use these large games or apps in the future, you can migrate them to another drive instead of deleting them. Windows Settings can help you with this task.

Step 1. Enter Settings in the Search dialog to open the Windows Settings

Step 2. Find the target Apps and programs by navigating to "Apps > Installed Apps" (In Windows 10, choose "Apps & features")

Step 3. Select the apps or games you want to transfer and click "Move"

Step 4. Select another drive as the destination, and choose "Move" to confirm the change

Transfer large games or apps from the C drive to another drive

Source: EaseUS

Tip 5. Discover hidden files in the C drive and delete them

Have you ever encountered a C drive that is full but has no files? If so, there may be hidden files that are occupying a lot of disk space on the C drive.

Here are some examples of hidden files:

  • System files: The operating system will hide system files that contain configuration settings, system preferences, and other data required for the functioning of the operating system to prevent the users from accessing or modifying them.
  • User's hidden files: Users may mark some files as hidden intentionally or unintentionally.
  • Configuration files: Many applications have configuration files that store settings, preferences, and other sensitive information. For data safety, they will be hidden.

In this case, you need to show hidden files and delete them.

Step 1. Type "Show hidden files" in the Search box to enter it in the File Explorer

Step 2. Click "View > Options" to open Folder Options or File Explorer Options, then open the "View" tab

Step 3. In Advanced settings, check the "Show hidden files, folders, and drives" box and select "OK"

Show hidden files on the C drive and delete them

Source: EaseUS

Step 5. Refer to tips 2 and 3 to clean up the unnecessary files and folders

Exercise caution when making system changes

Removing temporary files and uninstalling unnecessary programs are the most secure and effective solutions. 

However, it is important to stay cautious when making changes to your system, especially if you are unfamiliar with the technical details. Always create a backup of your important data and settings before making any major changes. Also, be careful when deleting system files or modifying system settings, as this can cause serious issues if done improperly.

If you are unsure about dealing with low disk space issues or need more advanced assistance, feel free to seek professional help. There are qualified technicians and IT support services available that can help you optimize your system and ensure it is functioning smoothly.

Learn more about data storage in this comprehensive G2 guide.

Edited by Shanti S Nair and Sinchana Mistry

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C Drive Full? Here are 5 Proven Fixes For a Full C Drive Stay calm when the computer warns you that the C drive is full with low disk space. Follow the tips and tutorials here, and you can efficiently get more free space to extend the c drive and improve computer performance.
Cedric Grantham Cedric Grantham is one of the senior editors and data recovery specialists of EaseUS who lives and works in Chengdu, China. He mainly writes articles and how-to tips about data recovery tutorials on PC and Mac. He has handled 10,000+ data recovery cases and is mainly good at data recovery of NTFS, FAT (FAT32 and ExFAT) file systems, and RAID structure reorganization of RAID 0, 5, and 10.

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