How to fix C drive running out of space issue

by John, Updated on: June 15, 2021

The same with old Windows XP, in Windows 7/8 and the last Windows 10, system C: drive is running out of space. To improve computer performance, many Windows 10 laptop and desktop are equipped with Solid State Drive (SSD) by DIY or from manufacturers. The read and write speed of SSD is much faster than traditional mechanical disk, so it is good to Operating System and applications. However, SSD is still very expensive, so it is much smaller. That means, system partition C has higher probability of running out of disk space.

It is easy to understand, Windows Updates, services, applications, browser cache and many other kinds of files are saved or generated in C drive continuously, sooner or later C drive runs low on free space. When C drive becomes full, it will be shown as red instead of blue in File Explorer.

C out of space

When system C drive is running out of free space in Windows 10/8/7, you'd better fix this issue as fast as possible. Otherwise, you'll suffer from computer performance down, system stuck, reboot unexpectedly or even crash. This article introduces a 3-step solution to fix C drive out of space in Windows 10/8/7 laptop/desktop fast and easily.

Step 1 - Clean up disk to reclaim free space

There are many unnecessary and junk files in C drive, by removing them you can reclaim disk space. To do this, Windows 10/8/7 have built-in Disk Cleanup utility which can delete common types of junk files easily and safely.

How to fix C drive running out of space in Windows 10/8/7 with Disk Cleanup utility:

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

cleanmgr cmd

Select C: drive and click OK.

Select drive

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

Select files

Confirm this operation by clicking Delete Files.

Confirm deleting

Repeat step 1, 2 and click Clean up system files in step 3.

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 methods to free up disk space in Windows 10 laptop/desktop.

Step 2 - Enlarge C drive as large as possible

You can reclaim disk space with Windows native Disk Cleanup or third party optimization software, but not all computers can regain plenty of free space. Even if you can get over 10GBs of free space, it will be eaten up quickly by new generated files. That means, C drive runs out of space in Windows 10/8/7 laptop/desktop again shortly. So you'd better expand C drive as large as possible.

With safe partition editor software, you can shrink a partition to release free space and transfer to C drive. In this way, there will be plenty of free space in C drive again without reinstalling Operating System or programs, everything (except partition size) keep the same with before.

Better than other utilities, NIUBI Partition Editor has unique 1 Second Rollback technology to ensure system and data intact. If anything goes wrong, it automatically reverts your computer to original status in a flash. In addition, it has Virtual Mode, Cancel-at-well technologies to avoid mistake and advanced file-moving algorithm to help resize partition 30% to 300% faster. It has free edition for Windows 10, 8, 7, Vista and XP home users.

How to fix C drive out of space in Windows 10/8/7 by adding free space:

  1. Download NIUBI Partition Editor free edition, right click D: drive and select "Resize/Move Volume", drag the left border towards right to shrink it and make Unallocated space on the left.
  2. Right click C: drive and select "Resize/Move Volume" again, drag right border towards right to merge this Unallocated space.
  3. Click Apply on top left to take effect, done.

D: drive here means the contiguous partition on the right side of C drive.

Follow the steps in the video to enlarge C drive with free space in another partition:

Video guide

Step 3 - Automatically remove new junk files

To completely fix C drive out of space issue in Windows 10/8/7 32/64 bit computer, you'd better continue this step. The larger C drive, the less probability C drive runs out of space again. However, you still need to remove new generated junk files. In Windows 7/8, you need to run Disk Cleanup utility monthly. But in Windows 10, you can free up disk space 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.

You have several options:

  1. Select the frequency to clean up disk space.
  2. Click the option to delete temporary files that aren't using.
  3. Select the options in drop-down list to delete files in Recycle Bin and Downloads folder one by one.

Free up automatically

In Summary

When system C drive is running out of space in Windows 10/8/7/Vista/XP, the right strategy is: free up disk space with Windows native Disk Cleanup to get some precious free space. Then expand C drive as large as possible. Finally, turn on Storage Sense to free up disk space automatically, or run Disk Cleanup utility monthly to remove new generated junk files. To fix Windows 10 C drive out out of space issue completely, every step is essential.