Solution - C drive is getting full in Windows 10

Updated on: May 17, 2019

This article introduces how to fix system C: drive full issue in Windows 10 (32 & 64 bit). Cleanup disk to remove unnecessary files and expand C drive to larger size.

Computer hardware price is much cheaper than ever before, so it is very common to use 1TB or 2TB hard disk for Windows 10 computers nowadays. To improve computer performance, more and more Solid-State Drive (SSD) are used for Operating System and applications, because the read and write speed is much faster than traditional mechanical hard disk. The large disk is used for data and backup.

However, no matter you use SSD or mechanical hard disk, system C: drive is getting full in Windows 10, because many kinds of files are writing into it continuously. It causes many issue if C drive is full, for example: Operating System runs much slower, stuck, reboot unexpectedly or even crash. To alert computer users, Windows convert this partition to red in File Explorer. In that case, you'd better try to solve this problem as soon as possible.

What is taking up space in C?

Windows 10 C drive full could be caused by both Windows and 3rd party applications.


It could be divided into 3 types of files:

1. Windows Updates

Due to technical bugs, security threat and other reasons, Windows automatically download and install Updates continuously. This is the top factor that cause C drive getting full, because there will be many and large Update files accumulating in C drive if you do not free up space.

2. Windows service

Windows service such as Paging File, Hibernation, Backup and Recycle Bin could take up several GBs space of each.

3. Other Windows files

Other files such as temporary, cache and logs are with small size but could be in large amount.


1. Installation 

The default installation path is in C drive, the more applications you installed, the less free space left. Some applications such as Games, Projects, Graphic and Videos eat large amount of free space.

2. Default output path

Some people like to use default settings when installing programs. It is not a good habit, you'd better install applications to other volume such as D. If you have installed to C drive, change the default output path to other large volume.

How to fix C drive full in Windows 10?

To completely fix C drive full issue, there are 3 steps you should do:

1. Free up disk space

Remove the unnecessary and junk files in C drive, then you can reclaim disk space to keep computer running in the right way. In addition, there is available space to install other program to help fix this issue. This step is very useful to the computer that never did this operation.

2. Enlarge C drive

With professional partition software, you can extend C drive by taking unused space from other drives in the same disk. This step is important especially to the computers that C drive are created small.

3. Use computer in right way

Running computer correctly is not only helpful to fix C drive full issue, but also helpful to improve computer performance.

Free up to reclaim disk space

Windows 10 has built-in Disk Cleanup utility to help clear up disk space, which can delete common types of unnecessary and junk files safely and easily, steps:

1. Press Windows and R key on keyboard, type cleanmgr, and then click OK.

cleanmgr cmd

2. Select C: drive and click OK.

Select drive

3. Click the check-box in front of the files that you want to cleanup and click OK.

Select files

4. Confirm this operation by clicking Delete Files.

Confirm deleting

5. Repeat to Clean up system files.

You may get several GBs free space if you did not clean up C drive before. If you want to reclaim more disk space, check additional steps to free up disk space on Windows 10.

You'd better enlarge C drive even if you got 10GB free space after freeing up, because these space will be eaten up quickly by new generated junk files. That means, you may encounter C drive full issue again and again.

Increase C drive to larger size

To do this, there is free partition software to resize allocated partitions and transfer more unused space to C drive. However, there is system damage and data loss risk when resizing disk partition with unreliable software, so remember to back up before this operation.

As the safest tool, NIUBI Partition Editor has powerful 1 Second Rollback technology to ensure system and data intact. If something goes wrong during the whole process, it automatically reverts your computer to original status in a flash. If it happens, nothing will be changed or damaged.

Download NIUBI Partition Editor and follow the steps in the video.

Video guide

Use computer in right way

As I said above, new junk files are keeping generated, so you'd better delete them regularly and make C drive clean.

Traditional method:

  1. Run Windows Cleanup as monthly maintenance utility.
  2. Install new applications to other volume instead of C drive.
  3. Change the output path of the applications to other large volumes.

New method:

Better than all previous versions, Windows 10 can complete this task automatically for you.

Firstly, you need to enable this service:

  1. Press Windows and X on keyboard, then Settings
  2. Go to System > Storage
  3. Switch Off to On under Storage Sense on the right side.

Storage sense

Then click Change how we free up space automatically below it.

You have several options:

Firstly, select from the list to free up disk space when this partition is running low or every day/week/month.

Then you can select wether delete temporary files automatically.

Then select from the drop-down list to delete files in Recycle Bin and Downloads folder if they have been there for over 1/14/30/60 days.

Free up automatically

After the steps above, you can fix C drive full issue for Windows 10 computers. If you still worry about the available space, there are 2 useful options (new features in Windows 10).

Move installed apps and games

Follow the steps:

  1. Press Windows and X on keyboard, then click Settings > Apps > Apps & features
  2. Click an app or game.
  3. Click the Move bottom.
  4. Select the new location from the drop-down list.
  5. Click the Move button.
  6. Repeat the steps to move more items.

Move Apps

Save files to new location

Windows 10 has new option to change where new content is saved for apps, documents, music, pictures, and videos to other place, steps:

  1. Press Windows and X on keyboard, then click Settings
  2. Click SystemStorage.
  3. Click Change where new content is saved under More storage settings.
  4. Click the drop-down list to select new location and click Apply.

Change location

In Summary

To fix C drive full in Windows 10: expand C drive as large as possible, reclaim disk space with Disk Cleanup, free up disk space once a month or set to work automatically. Move applications and files if you want.