EaseUS Partition Master

Easily manage your disk partitions with this trusted software.

  • Convert MBR to GPT for Windows 11.
  • Migrate Windows 11 to New SSD in 1-Click.
  • Extend C Across Disks, Fix Low Disk Space Error.
Free Download 

Windows 11/10/8/7100% Secure


Total downloads

Page content

Extend C drive or system partition in Windows 11/10

Updated by Tracy King on Aug 27, 2021
mins read

Page Content:

  1. 3 Ways to Increase C Drive Space in Windows 11/10
  2. Upgrade to a Larger Hard Drive Without Data Loss
  3. Tips to Extend C Drive in Windows 11/10
  4. Related Questions on Extending Partition Windows 11/10

Windows 11/10 C drive is out of space:

Windows 10 C drive out of space

When the C drive (system partition) is out of space, gets full or you get a low disk space warning, and hardware upgrades become unavailable shown as the next image, what are you going to do? How to extend C drive or system partition in Windows 11/10? Follow the tips below, you'll learn how to extend partition, especially to increase C drive in Windows 10. 

1 - Extend C Drive or System Partition in Windows 11/10

For users who want to extend C drive with a professional and easy method, EaseUS Partition Master is the right choice for you.

Solution 1. Let EaseUS Partition Manager Software Help

As magic partition software, EaseUS Partition Master is a comprehensive hard disk partition management software to let you enjoy free with all the powerful functions:

  1. 1. Extend system partition
  2. 2. Resize and Move partitions
  3. 3. Copy Partition/Disk
  4. 4. Create, Deleted, and Format partitions
  5. 5. Hide and Unhide partitions and more... 

This software works perfectly with hardware even with RAID and supports all Windows Operating Systems. Your data is completely protected during all operations.

Free Download 

Windows 11/10/8/7100% Secure

Tutorial 1. Smart Extend C Drive with Low Disk Space Error

Step 1. Click "Adjust with 1-Click" to extend C drive.

When your C drive is out of space, you will see the Low Disk Space alert on EaseUS Partition Master. Click the Adjust button to extend it.

How to Adjust Low C Drive Space Step 1

Step 2. Click "OK" to extend C drive automatically.

By clicking "OK", EaseUS Partition Master will automatically allocate space to your C drive to solve the low space issue.

How to Adjust Low C Drive Space Step 2

Extra Option: You can also click "Manual Adjustment" to extend the C drive manually.

When turning to Manual Adjustment, select the C drive, and drag dots rightward to add more space to C drive. Click "OK" to confirm.

Manually Adjust Low C Drive Space

Step 3. Confirm to resolve low disk space in C drive

Click the "Execute Operation" button at the top corner and start all pending operations by clicking "Apply".

How to Adjust Low C Drive Space Step 3

Tutorial 2. Add Space to C Drive, Extend System Drive with Space from Other Drive

Option 1. Extend System C drive with unallocated space

  1. 1. Right-click on the System C: drive and select "Resize/Move".
  2. 2. Drag the system partition end into the unallocated space so to add it to the C: drive. And click "OK". 
  3. 3. Click "Execute Operation" and "Apply" to execute the operations and extend the C drive.

Option 2. Extend System C drive without unallocated space

  1. 1. Right-click a big partition with enough free space on the system disk, select "Allocate Space".
  2. 2. Select the system drive at the Allocate Space From (*) To section, and drag the end of System C drive into the unallocated space. Click "OK" to confirm.
  3. 3. Click "Execute Operation", it will list the pending operations, and click "Apply" to save the changes and extend the C drive.

0:00-0:32 Extend System Drive with Unallocated Space; 0:32-1:00 Extend System Drive without Unallocated Space.

  1. The program may pop up a window to ask you to restart your computer after executing the operation, do as the software requires.
  2. Your computer will restart with a bigger system C drive and better computer performance on your Windows 11/10 PC.

Besides the basic and advanced partition manager features, EaseUS Partition Master also provides a powerful partition recovery wizard to recover deleted or lost partition, cleanup and optimization for optimizing hard disk and clean up disk space, wipe data to permanently erase hard drive/partition, and so on.

Solution 2. Extend C Drive Windows 11/10 via Disk Management

There must be unallocated space behind the partition which you want to expand with Windows built-in Disk Management utility. Otherwise, you might find that the Extend Volume option is greyed out and not available.

Step 1. Right-click My Computer and choose "Manage -> Storage -> Disk Management".

Step 2. Right-click on the partition that you want to extend, and choose "Extend Volume" to continue.

extend windows 10 partition

Step 3. Set and add more size to your target partition and click "Next" to continue. 

Extend Windows 10 partition with Disk Managenent

Step 4. Click "Finish" to complete the process.

Solution 3. Extend C Drive Windows 11/10 via CMD

There is another tool named Diskpart which also enables you to manage your disk and partition. The Windows Command Prompt works the same as Disk Management. One important point is that inexperienced users should not rush to this method because a tiny mistake is able to do damage to the entire hard drive. 

Step 1. Press Windows + X keys and choose "Command Prompt (Admin)".

Step 2. Type the following commands and each one ends with "Enter" key:

list volume
select volume x
extend size =number

In my case, the system C drive is Volume 1. If there is no unallocated space, you can't extend C drive in Windows 11/10 with this method.

extend c drive using cmd

2 - Upgrade to a Larger Hard Drive Without Data Loss

Clone and replace the old drive with a bigger one can also solve your problem. If you don't want to migrate other data on C drive, you can only migrate the Windows operating system to a new drive. 

Video Tutorial: How to migrate OS from HDD to SSD

Free Download 

Windows 11/10/8/7100% Secure

If you want to replace the whole C drive both the system and the data, clone this drive with the help of EaseUS Partition Master. This feature enables you to move your system and data to SSD/HDD easily and quickly. Follow the steps below to clone your drive:

Step 1. Right-click the partition you want to copy, and choose Clone.

Step 2. Choose your the target partition and click Next to continue.

  • If you clone partition to the existing partition, you should transfer or back up data before cloning to prevent it being overwritten.

Step 3. Click Proceed and wait for the clone to complete.

You can check how to clone partition or system reserved partition on this video tutorial.

Also Read: How to Partition A Hard Drive in Windows 11/10

Tips to Extend C Drive in Windows 11/10

In addition to these solutions, you may ask the way to extend C drive in Windows 11/10 without software. Here, you can learn some other tips to reduce the possibility of C drive full and increase C drive space.

1. Move the print spooler and page file to another drive.

2. You can also merge other partition into C drive for more space.

3. Apply professional partition manager software with the Cleanup and Optimization feature that can also speed up your slow computer, clean up those junk files and repair the Windows system. This will save you a large amount of space on the C drive and other partitions.

4. Empty recycle bin. Recycle bin is a storage room for all the files you delete from your PC. The deleted files remain there until you delete files from the recycle bin. Usually, the recycle bin takes up C drive space. That is to say, when you empty the recycle bin, you can increase a bit of disk space.

  • Right-click on the recycle bin icon located on your desktop and select "Empty Recycle Bin".
  • Or double-click on the recycle bin and click on the "Empty Recycle Bin" option located on top of the folder window.

Related Questions on Extending Partition Windows 11/10

In addition to extending the C drive, some people have asked related questions. Here are some examples:

1. Can we extend the C drive?

Yes, you can. You can use the third-party software, Disk Managemen or Diskpart to easily expand your C drive in Windows 11/10. Among them, EaseUS partition software is my recommendation. It can extend any drive easily and quickly.

2. How do I add storage from D to C?

Let EaseUS partition software help you. Launch EaseUS Partition Master and locate the target partition which you would like to extend. If there is unallocated space left on your disk, use the "Resize/Move" feature to extend partition. If there is no unallocated space on your disk, use the Allocate Space feature to extend the desired partition.

Free Download 

Windows 11/10/8/7100% Secure

3. Why extend volume grayed out windows 11/10/8.1/7?

When you are using Disk Management to increase C drive space, you can right-click "Computer", choose "Manage" to go, then you can enter "Disk Management". If you see the Extend Volume option grayed out on your computer, it means that there is no unallocated space on your hard disk.

4. How to add space to C drive?

  • Launch EaseUS Partition Master.
  • Right-click on the System C: drive and select "Resize/Move".
  • Drag the system partition end into the unallocated space.
  • Click "Apply" to execute the changes and extend the C drive.

How Can We Help You

About the Author

Updated by Tracy King

Tracy joined in EaseUS in 2013 and has been working with EaseUS content team for over 7 years. Being enthusiastic in computing and technology, she writes tech how-to articles and share technical solutions about Windows & Mac data recovery, file/system backup and recovery, partition management and iOS/Android data recovery.

Read full bio

Product Reviews

Product Reviews

TrustScore 4.7 | 49 reviews
  • I love that the changes you make with EaseUS Partition Master Free aren't immediately applied to the disks. It makes it way easier to play out what will happen after you've made all the changes. I also think the overall look and feel of EaseUS Partition Master Free makes whatever you're doing with your computer's partitions easy.

    Read More
  • Partition Master Free can Resize, Move, Merge, Migrate, and Copy disks or partitions; convert to local, change label, defragment, check and explore partition; and much more. A premium upgrade adds free tech support and the ability to resize dynamic volumes.

    Read More
  • It won't hot image your drives or align them, but since it's coupled with a partition manager, it allows you do perform many tasks at once, instead of just cloning drives. You can move partitions around, resize them, defragment, and more, along with the other tools you'd expect from a cloning tool.

    Read More

Get EaseUS Partition Master

Your best companion for disk partitioning, MBR to GPT/GPT to MBR conversion,even OS migration

Free Download 

Windows 11/10/8/7100% Secure