Extend C drive

How to add free disk space to C drive?

All disk partitions are allocated while building the computer, is it possible to resize the partitioned drive without starting from scratch? Yes, it is. Windows built-in Disk Management has Shrink Volume and Extend Volume functionalities to change partition size. However, if you want to add free space to C drive from D with Windows Disk Management, you’ll be disappointed. Extend Volume is disabled for C drive after shrinking D, so you cannot extend C drive with the free space except that you can move volume D to the right side.

In this article, I’ll show you how to add disk space to C: drive from D or any nonadjacent drive with free partition software.

Add space to C

Benefit to add disk space to C drive

Most of the Windows computer users will or have encountered the problem that system C: drive is running out of space and the annoying Low Disk Space alert pops up frequently. If it happens, the fastest way to solve this problem is by extending C drive. That means add more free space to C drive from other partitions. It may cost a whole day if you back up everything, delete and recreate partition, restore and verify data.

However, not every partition software can complete this task well. There is data loss and system damage risk while re-partitioning disk drives with 3rd-party program. To resize partitioned drives, the parameters in MBR, DBR and other place of related disk, volume and files should be modified correctly. Any software error or hardware issue such as power failure will cause part of the parameters unable to be modified. In this case, system, partition and/or data will be damaged. So the first and most important step is selecting a reliable and safe partition software.

Thanks to the built-in unique 1 Second Rollback technology, NIUBI Partition Editor is the only program that can ensure 100% everything intact. Really? Yes, because it can automatically roll back the computer to the status before these operations in ONE second, no matter any software related error or hardware issue occur. That means nothing will be changed or lost if something goes wrong.

Add free space to C drive from D drive

If you use Windows 10, 8, 7, Vista or XP (32 and 64 bit), you may use NIUBI Partition Editor Free Edition to complete this task easily.

Step 1: Download NPE Free edition, right click D drive and select Resize/Move Volume.

Shrink D

In the pop-up window, drag left border rightwards to shrink D.

Shrink D

20GB free space is released from drive D and shows as Unallocated space behind C drive.

Unallocated created

Step 2: Right click C drive and select “Resize/Move Volume” again. In the pop-up window, drag the right border rightwards to combine the Unallocated space.

Extend C drive

Step 3: Click Apply on top left to execute, done. 20GB free space is added to C drive from D drive.

C drive extendedNote: the operations listed below Pending Operations with tick can be done in Windows without reboot.

Add space to C drive from nonadjacent partition

In some situations, there is not enough free space in the adjacent volume D: (or with other drive letter), in the case, you can transfer free disk space from other partitions and add to C drive. Only an addition step to move partition is needed.

To better understand how to add space to C drive from any nonadjacent volume, I suggest you watch the video, which is created on Windows 10, but the steps are valid to other Windows versions.


Note: If you use Windows Server 2016, 2012, 2008, 2003 or Small Business Servers, the free edition cannot help you. All server partition software are commercial, but it is worth to pay for such easy and safe partition tool for servers.