Fix Windows 10 low disk space issue

Updated on: May 17, 2019

Low disk space issue is very common in Windows 10 especially to system partition C, but few people know how to solve this problem. In this article, I'll explain why system C drive runs low on disk space and how to fix Windows 10 Low Disk Space issue with detailed steps.

Symptom of low disk space

When any hard drive partition becomes full and the free storage space is less than 10%, C drive will be shown as red instead of the default blue bar in File Explorer. which is to alert people fixing this issue as fast as possible.

Red bar

When C drive is showing red, you'll suffer from computer performance down. It may stuck when you do some operations, or reboot unexpectedly. In this situation, if Windows 10 download and install Updates, C drive may be full immediately.

When free space reach the threshold, Windows 10 will pop up an notification 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."

Low storage space

If free space is keep running low, Windows 10 will pop up another notification with message "Your computer's running low on storage space. Visit storage settings to free some up".

Low disk space

Why Windows 10 runs low on space

Windows 10 low storage space maybe caused by several reasons including:

  1. Virus attack
  2. Display incorrectly
  3. fill up with junk files

If the computer was attacked by some particular virus, large amount of files will be generated. If C drive has plenty of free space but becomes full in a short time, you'd better run your antivirus software to scan.

In previous Windows Vista and Windows 7, some people feedback such issue that C drive usage percentage is showing incorrect, but in Windows 10 this problem seems to be solved, however, it is still a possible reason.

The most possible reason is that C drive is filling up by many types of files. Windows 10 download Updates frequently. Temporary, log, hibernation, backup, internet browser cache also eat up free space quickly. Furthermore, many people install applications to system partition C. The more you installed, the less free space left. Many applications for Games, Projects, Videos and Photograph will output very large files. If you do not pay attention, C drive is running low on space very quickly even if you create it very large.

How to fix low disk space issue

To fix Windows 10 low disk space issue completely, you should follow 3 steps:

Steps 1: Clean up disk to remove junk files

When the low disk space notification pops up, you may turn on storage sense and click the "Free up storage space" windows to reclaim disk space, or run the standalone Disk Cleanup utility.

  1. Press Windows and R on your keyboard, type diskmgr and press Enter.
  2. Select C: or other drive that is running low.
  3. Select the files you want to delete and click OK.
  4. Repeat to Clean up system files.

This step is useful to the computers that never or have not free up space for a long time. By doing this, you may reclaim over 10GB free space.

However, free space may be eaten up quickly by new generated junk files. If you cannot get over 20GB free space or C drive was created small, you'd better transfer more unused space from other partitions.

Clean up

Steps 2: Enlarge C: drive

The hard disk drives are allocated while installing Windows, but you can extend C drive with unused space in other data partition without reinstalling. This step is very important to the computer that use SSD and C drive was created small. Otherwise, you may encounter the low disk space issue again and again.

(Take smart phone as example, if you use a 16GB device, you have to clean up very frequently, but you won't encounter this issue for such a long time if you use a 256GB device.)

Download NIUBI Partition Editor and follow the steps to enlarge C: drive.

Video guide

Besides resizing and extending disk partitions, this tool helps you move, merge, copy, convert, defrag, wipe, hide partitions and scan bad sectors, etc.

Steps 3: Remove junk files automatically

Better that all previous versions, Windows 10 has the ability to remove junk files automatically. So, it can keep you C drive always clean.

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

Steps 4: Change location for new files

Some types of files such as apps, documents, music, pictures, and videos are not junk but keep increasing.

As another wondering feature, Windows 10 can save new these types of files to other partition.

  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

After finishing the steps above, you can fix low disk space issue on Windows 10 computer completely.