What Happens When C Drive is Full? [Solutions Included]

What happens when C drive is full? Generally, your computer will slow down slightly or significantly then. Here, we offer effective solutions to C drive full in Windows 11, 10, 8, 7 to keep your computer at its best.


By Emily / Updated on May 12, 2023

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What will happen when C drive is full?

The C drive always means the system drive, which contains the operating system and the related system files. It is considered as the primary hard drive of the system. If the C drive fills up, you will find the C drive bar is red in Windows File Explorer. Besides, you will receive an error message on your computer that says: Low Disk Space. You are running out the disk space on Local Disk (C:). Click here to see if you can free space to this drive.

C Drive Full

When the error message or red bar appear, you will find the PC slows down obviously. Also, you cannot store any new data or install new programs onto the C drive. What’s worse, you may fail to finish important operating system and software update or upgrade since there is not enough free space. All in all, your computer will work less efficiently when C drive is full.

C drive full solutions

Since many issues can be triggered when C drive fills up, it matters a lot to find corresponding solutions. If you wonder what’s taking up the C drive space, you can use “Storage sense” to understand how the storage is being utilized on Windows computer. Next, it’s time to learn what to do when C drive is full in Windows 11, 10, 8, 7.

Storage Setting

Solution 1: Clean Recycle Bin and Delete Temporary files

When your C drive is full, it is recommended that you run Disk Cleanup to clean up the C drive prior to performing any other further operations.

Step 1. Open File Explorer, right click on your C drive and choose "Properties".

Step 2. When the Properties dialog opens, click the Disk Cleanup button.

Step 3. Windows will scan your C drive and calculate how much space you can free from this drive.

Step 4. Select the files you want to delete and click "OK". You can also click "Clean up system files" button to delete system files. From there, you are able to delete previous Windows installation (Windows.old folder), system restore points, Recycle Bin, and other system files.

C Drive Cleanup

 Typically, this can help you free up at least a few gigabytes or more of free space on your C drive. If this does not help a lot, read on for more advanced methods.

Solution 2. Move big programs from C drive to another drive

For most users, the first measure should be uninstalling some unnecessary programs from C drive after they know what happens when C drive is full. What if all applications are required and cannot be deleted? In such a case, you can move programs to another drive that has enough free space. For this app migration task, the AOMEI Partition Assistant Professional is worth trying. Its "App Mover" can help move applications from one partition to another partition and make them stay bootable afterwards. You can download the demo version.

Download Free DemoWin 11/10/8.1/8/7/XP
Secure Download

Step 1. Install and run AOMEI Partition Assistant Professional. Click "Free up" -> "App Mover".

App Mover

Step 2. In the pop-up window, choose C drive and click "Next".

Select Partition

Step 3. Now, you can see all movable apps on C drive. Choose one or more apps that you need to move and the destination partition. Then click "Move" to execute the operation.

Tick Apps

Step 4. Confirm that you have closed apps that will be moved. Then, click "OK".


Step 5. Wait for the process to complete. Then, click "Finish".


After the move, you can also try "Delete Large Files" to deeply clean your PC.

Solution 3: Enlarge C drive space

The above two methods focus on releasing space on C drive. Now we will teach you how to enlarge the C drive space. This can also be easily achieved by AOMEI Partition Assistant Professional software. Its "Merge Partitions" to combine two adjacent partitions into one, or merge unallocated space into partitions (no matter whether they are contiguous or not). Besides, its "Allocate Free Space" can directly transfer one partition’s free space to another partition. The detailed steps are listed as below.

Step 1. Right-click the partition which you want to allocate free space from and select "Allocate Free Space". 

Allocate Free Space

Step 2. Type in the size of the free space and select C drive as the destination partition.

From D to C

Step 3. Click "Apply" to execute this operation.



This post tells not only what happens when C drive is full, but also what to do if the C drive fills up. Now, you can easily solve the C drive full issue no matter whether you want to free up its space or enlarge the space. To avoid C drive space being used up quickly, it is better to change default download location.

Emily · Staff Editor
Emily is an English editor of AOMEI Technology; she has a great passion for providing easy solutions for people to tackle with all disk or partition management problems. In addition to writing articles about disk/partition management, she also edits great tutorials on how to back up and restore disk for data security. In her spare time, she loves to learn computer skill to improve herself or stay with her family to enjoy a good day.