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[100% Fixed] Can I Extend C Drive from Another Disk in Windows 10/11?

Updated by Tracy King on Feb 22, 2023

Extending a C drive from another disk is easy, but few software or methods can do this directly. Don’t worry. The plans on this article can instantly expand the C drive while two volumes are NOT on the same HDD or SSD.

Situations Step-by-step Troubleshooting
One system disk, no unallocated space. Try new features of EaseUS Partition Master...Full steps
One system disk has an adjacent drive or unallocated space. Use Diskpart to delete adjacent drive and use unallocated space...Full steps

Do you have the same question about extending the OS drive? See the new quiz from superuser.com.

"Expand C: with another Hard Drive? I have two hard disks of 30GB each......I want to use the second hard drive to expand the space of my first hard disk. Is there any way to do this? (Without having to reinstall everything?) Windows 8 after two days have already used 25GB......"

Once your C drive runs out of space, the cache files generated by apps and other installed programs will make your device slower than ever. As a result, you may encounter high disk usage, and Windows OS update stuck, etc.

If you are experiencing such a case, the best fix is to increase C drive space on the first disk. Here is a powerful and safe disk partitioning software to help you!

Use Professional Software to Extend C Drive from Another Disk

Is c drive full? Get a "Low Disk Space" message? I often meet this warning a lot before I get a new game downloading or upgrading Windows OS, so I also want to recommend this resolution - EaseUS Partition Master - for you to get space on the system drive. EaseUS Partition Master has released a new feature, which allows you to extend space from another disk. 

In the case of insufficient space (“Low Disk Space” warning received), there is a second disk, and sufficient space is available. If your system disk has only one C partition, you can use this software to create a new section on the second disk without deleting any data. The programs and data in the system partition are automatically migrated to the new disk to expand the original space of drive C. 

More info about EaseUS Partition Master: 

EaseUS Partition Master

  • Resize, delete, create, format, shrink partitions effectively.
  • Convert MBR to GPT or vice versa, convert primary to logical partition.
  • Support to clone HDD/SSD and migrate OS to hard drive.
Free Download 

Windows 11/10/8/7100% Secure

How to Extend C Drive from Another Disk with EaseUS Partition Master

Here you can get an in-depth guide and some notes. Remember that do not select external devices during execution and do not abort partition creation. 

Some tips about using this feature:

1. Will this function transfer all files from the C drive? 

No, Windows components and personal desktop data are protected and not migrated.  

2. Can I select the third disk?

If multiple disks exist, you can select the second or third disk to relocate the disk.  

3. What about capacity or speed limit? 

There is no limit on the capacity of data to be migrated, and the migration speed is related to the data size. The migration speed is the same as the Copy speed of Windows.  

4. Can I check the new partition with the Windows built-in tool?

The newly created migrated partition can be edited using Disk Management.  

Free download EaseUS Partition Master:

Free Download 

Windows 11/10/8/7100% Secure

A step-by-step guide to using the feature:

Step 1. Launch EaseUS Partition Master and go to Partition Manager. Right-click the system C drive, select "Advanced", and click "Extend with 2nd Disk".

extend c drive with second disk 1

Step 2. After the software analyzes the status of the disk and lists the extended results, click "Customize Plan" to continue.

extend c drive with second disk 2

Step 3. Select the listed data to migrate, or click the location to select more, and then click Next to continue.

extend c drive with second disk 3

Step 4. Select which partition to column the expanded C partition after, for example, G, and click"Proceed".   

extend c drive with second disk 4

Another Manual Way in Windows 10/11: Extend C Drive with DiskPart

Note: This part is not related to extending C drive space from another disk. Need to backup in case of data loss.

Diskpart can help you get more space on C drive. Still, it has restrictions: If you only get one C drive and no unallocated space behind, revert to the software part to extend the system drive from another hard drive using EaseUS Partition Master. If you get another adjacent drive behind C drive, you can delete it with Diskpart and increase C drive space.

Step 1. Type cmd on the search box. Right-click cmd and click "Run as administrator."

Step 2. Type diskpart and press Enter.

Step 3. Input command lines and hit Enter each time:

  • list disk
  • select disk * (Replace * with the disk number of your system disk. Like select disk 0.)
  • list volume
  • select volume * (Replace * with the partition number. Please back up important files on volume first.)
  • delete volume
  • select volume * (Replace * with the disk number of your C drive.)
  • extend size =number (Normally, the default size unit is MB.)
  • Exit

Then you can restart the computer, and your C drive is expanded.

Final Thoughts

In this article, we've introduced one incredible partition software - EaseUS Partition Master. So if you got one system disk and no unallocated space to extend the C drive, you could resort to the second disk (No external device.) That’s the easiest way we tested. Wish this software can help you.

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About the Author

Updated by Tracy King

Tracy joined in EaseUS in 2013 and has been working with EaseUS content team for over 10 years. Being enthusiastic in computing and technology, she writes tech how-to articles and share technical solutions to resolve Windows & Mac data recovery, data backup, partition management, data transfer, Windows update issues, etc.

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Product Reviews

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  • 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.

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  • 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.

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  • 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.

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