C drive running out of space on Windows 10

Updated on: November 16, 2019

This article introduces why system partition C is running out of space on Windows 10, and what to do when C drive runs low on disk space.

Why C drive is running out of space in Windows 10

As the latest Windows client Operating System, the strategy to organize and manage files of Windows 10 has no much difference with previous versions. So, low disk space is still very common issue in Windows 10. Many people feedback that system C drive is running out of space. To better solve this problem, you should first know why C drive runs out of space on Windows 10 desktop or laptop.

Programs installation

All programs use system partition C as default installation directly and many people do not change the path manually. The more programs you installed, the less free space left in this partition. Furthermore, some programs for pictures, videos, games and special projects produce many large files. This is the reason why C drive getting full in a short time to a new computer.

Windows Services

The same with old versions, Windows 10 also download and ask you to install Updates continuously. Each Update uses hundreds MBs to several GBs.

Other services such as System Protection and Hibernate could produce files larger than 10GB.

Junk files

Both Windows and third party programs could generate temporary files and other junk files. These files are not large but there could be large amount.

Many Windows 10 users have SSD for Operating System and programs. It is good for performance but is small because of high price. If you do not create C drive as large as possible and use the computer in right way, C drive runs out of space in a short time.

What to do when C drive runs out of space

When system C drive is running low on space, there are two necessary steps and one optional step.

Firstly, you should delete the junk files. These files can be removed safely by Windows 10 built-in Disk Cleanup utility. Then, move the installed programs and some other files out from C drive. If you cannot get enough free space, you'd better add more unused space from other partition.

Remove junk files to regain free space (necessary)

Step 1: Press Windows and R on the keyboard, type cleanmgr and press Enter.

Launch Disk Cleanup

Step 2: Select C: drive or any other one from the drop-down list and click OK.

Select drive

Step 3: Click the check-boxes in front of the files that you want to remove. Read the associated description on bottom before clicking OK if you do not know these files are about.

Select files

Step 4: Click Delete Files to confirm.


Disk Cleanup will begin clearing up, the time depends on your computer performance and the amount of files.

Clearing up

Step 5: Repeat to clear up system files (optional).

See complete solution to free up disk space on Windows 10.

Move programs and files (necessary)

Windows 10 has the ability to move non-essential programs to other volume directly without reinstalling.

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 (optional)

Better than old versions, 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

Allocate more free space from other volumes (optional)

If you did not get large amount of free space in C drive after freeing up and moving programs, you may encounter C drive out of space problem again shortly afterwards. In that case, you'd better transfer unused space from other partitions.

There is free partition software such as NIUBI Partition Editor, which can shrink any data volumes to release free unused space, and then add into system C drive.

Download NIUBI Partition Editor Free and follow the steps to shrink drive D and expand C:

Step:1 Right click drive D and select "Resize/Move Volume", drag left border towards right in the pop-up window.

Shrink D

Then 20GB unused space is converted to Unallocated on its left side.

Shrink D rightwards

Step:2 Right click drive C and select "Resize/Move Volume" again, drag right border towards right.

Extend C drive

Then Unallocated space is combined into C drive.

Extend volume C

See full solution to allocated space to C drive in Windows 10 without losing data.

Windows 10 C drive out of space issue is annoying, because it may come out again and again. Follow the methods above, this problem can be solved permanently or for a long time.