Solution - C drive is getting full in Windows 10

by John, Updated on: February 22, 2021

This article introduces how to fix system C: drive full issue in Windows 10 (32 & 64 bit). Clean up disk to remove unnecessary files and add more free space to C drive from other partitions.

The same with all previous versions, Windows 10 C drive becomes full at a certain time, because many kinds of files are writing into it continuously. More and more Windows 10 laptop and desktop use SSD for Operating System and applications, because the read and write speed is much faster than traditional mechanical hard disk. But on the other hand, SSD is much more expensive, so it's not very large to common users. Therefore, there's higher risk that system C drive becomes full in Windows 10 computers.

When C: drive is getting full, Windows 10 will pop up a warning message on bottom right and ask you to turn on storage sense - "Your PC's low on storage. Turn on storage sense and Windows can help free up space." In addition, to alert computer users, Windows mark C drive as red in File Explorer. When C drive is almost full in Windows 10 laptop/desktop, you'd better try to fix this issue as fast as possible. Otherwise, your Operating System runs much slower, stuck, reboot unexpectedly or even crash.

Many people said that "my C drive is full without reason in Windows 10 laptop", but in most cases, C drive free space is taken up by many kinds of files.

What is taking up space in C drive in Windows 10?

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


1. Windows Updates

Due to technical bugs, security threat and other reasons, Windows automatically download and install Updates continuously. There will be large amount of Update files accumulating in C drive if you do not clean up disk.

2. Windows service

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

3. Other Windows files

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


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

Many people like to use default settings when installing programs, therefore, these programs output many files in C drive. Some people feedback that "my C drive is suddenly full in Windows 10 computer", because C drive is not big and they throw everything into it. You'd better install programs and change associated output path to a separate partition, otherwise, your C drive will be full in a short time even if your computer is new.

How to fix C drive full in Windows 10?

To completely fix C drive full issue in Windows 10 laptop/desktop, there are many methods but following 3 steps are most important and efficient:

  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 clean up disk.
  2. Add more free space to C drive
    With partition editor software, you can increase C drive space by taking unused space from other partition on the same disk. This step is very 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.

Step 1 - Clean up disk to reclaim free space

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

How to clean up disk when C drive is full in Windows 10:

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

cleanmgr cmd

Select C: drive in the drop-down list and click OK.

Select drive

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

Select files

Confirm this operation by clicking Delete Files.

Confirm deleting

Repeat step 1, 2 and click Clean up system files on the bottom.

If you cannot reclaim more than 10GB free space in C drive, you'd better add more from other partition. Otherwise, these free space will be eaten up quickly by new generated junk files. That means, you may encounter C drive full in Windows 10 computer again in a short time.

Step 2 - Add free space to C drive from other partition

To do this, NIUBI Partition Editor has free edition to help you. It is able to shrink other volume to release free space and then add into C drive. Your Operating System, programs and anything else keep the same with before.

Download the free software and follow the steps to extend partition when C drive is getting full in Windows 10/8/7.

Video guide

Besides extending C drive, this free partition manager helps you do many other operations such as copy, merge, convert, defrag, hide, wipe partition, scan bad sectors, etc.

Step 3 - Use computer in right way

No matter you use Windows 10/8/7 or the old Windows Vista/XP, when system C drive is getting full, you'd better complete the additions steps:

  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.

Better than all previous versions, Windows 10 has new features to help fix low disk space issue on C drive.

① Clean up disk automatically

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.

  1. Select frequency in the drop-down list.
  2. Select whether delete temporary files automatically.
  3. 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

② Move installed apps and games

In all previous version, you have to reinstall all programs if you want to change location of them, but in Windows 10, you can move them to another partition directly.

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 button.
  4. Select the new location in the drop-down list.
  5. Click the Move button.
  6. Repeat the steps to move more items.

Move Apps

③ 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

Follow the methods above, you can fix Windows 10 C drive full issue completely.