If your Windows 10 drive is running low on disk space, there are plenty of ways to free up some valuable space on the drive. The best way is to run a junk cleaning software like CCleaner (if not done already), and uninstall unwanted software. If that’s not possible, extend your system partition size.
If you have tried all other possible options to free up the disk space, you can consider the compress OS feature in Windows 10 to free up a considerable amount of space. It will compress all the files and folders that are part of the operating system. And unlike the NTFS compression (which has been part of all recent versions of Windows), this compress OS feature will not degrade your system performance.
By compressing the operating system, you can free up around 2 GB of free space. The compress OS is instructed first with Windows 10 and is not present in its predecessors.
WARNING: Although the method is safe, we recommend you create an image backup of Windows 10 just in case if something goes wrong.
Method 1 of 2
Compress Windows 10 OS to free up disk space
Step 1: Open Command Prompt as administrator. To do so, type CMD in Start menu search box, right-click on Command Prompt in search results and then click Run as administrator option.
You can also right-click on the Start button and then click Command Prompt (admin) to open elevated Command Prompt.
Click Yes button when you see the User Account Control dialog.
Step 2: Before actually beginning to compress the operating system, it’s a good idea to check the status of the compact state. In the elevated Command Prompt, type the following command and press Enter key to know the status of the compact state.
The message “The system is not in the compact state because Windows has determined that it is not beneficial for this system” indicates that Windows 10 is not compressed using the compact OS feature. The tool is showing “not beneficial for this system” likely because Windows 10 was installed on a large drive.
And if the compact state is enabled, you will get “The system is in the compact state. It will remain in this state unless an administrator changes it” message.
Step 3: To compress your Windows 10 OS, type the following command, and press Enter key.
Depending on the size of the data on drive where Windows 10 is installed and your PC’s hardware configuration, Windows might take up to an hour to complete the job. Once done, check the drive properties to know how much space you gained by compressing Windows 10 OS.
You should be able to free up at least 2 GB of free space by compressing the Windows 10 operating system.
Uncompress Windows 10 install
To turn off compact state feature and uncompress Windows 10, execute the following command.
Method 2 of 2
Compress Windows 10 using the NTFS compression method
As mentioned before, compressing operating system files might degrade Windows 10 performance. If possible, we suggest you avoid compressing Windows 10 install and use other ways out there to free up some space on the system drive.
Please note that this NTFS file compression feature is available only if the drive where Windows 10 is installed is using NTFS instead of other file systems. To check the file system type, right-click on the drive, and then click properties.
NOTE: It’s hard to tell the exact amount of space you will gain by compressing your Windows 10 install files and folders. On our Windows 10 Pro (x64), we managed to free up a little more than 1.5 GB of space. Depending on the total size of the data on the drive, you might be able to free up less or more.
Step 1: Open up File Explorer, right-click on the drive where Windows 10 is installed (usually “C” drive), and then click Properties option.
Step 2: Under the General tab, check the box labeled Compress this drive to save disk space, and then click Apply button.
Step 3: When you see the following confirmation dialog, make sure that the select option labeled Apply changes to drive, subfolders, and files before clicking the OK button.
Depending on the total size of the data on the drive, Windows 10 might take a couple of minutes to hours to complete the compression.
Once the compression is done, all files and folders on your Windows 10 drive will have blue icons, as shown below. These icons also appear on files and folders on the desktop.
To uncompress Windows 10 install drive
Step 1: Right-click on the drive where Window 10 is installed and then click Properties to open drive’s properties dialog.
Step 2: Under the General tab, deselect the option labeled Compress this drive to save disk space and then click Apply button.
Step 3: When you see the following confirmation dialog, click the OK button.