By AOMEI / Last Updated July 26, 2019

Why Need to Increase C Drive Space From D Drive?

Most computer users have encountered such problem: As time goes by, the Windows operating system C drive becomes slower and slower and it is running out of space! While, the other partitions, like D drive, still have much free space. The distribution of free space is out of balance now though it wasn’t when you newly using the computer. It is sure that most people have allocated disk space to each partition on balance, even more space to C partition for achieving better system performance. However, C drive still dies out of space much earlier than the other partitions. The causes may be many programs are installed on system partition, large amount of data are stored on system drive, OS running generated a lot of extra files, etc. Anyway, how to solve such issue?

Maybe some green hands think about uninstall some non-frequently used tools or reinstall them on other partitions, delete unnecessary files or move data on C drive to other drives, etc. It does help but not too much, and the processes are troublesome and time-consuming. Is there another easier way?

Of course, you can deal with low disk space problem on C drive by thinking from another point of view – increase c drive space from d drive. Then, how to allocate free space to C drive?

How to Increase C Drive Space from D Drive?

Generally, there are two ways, using Disk Management (DM) or by partition software – AOMEI Partition Assistant.

How to increase space in C drive using disk management?

The premise of DM increase C drive space is that there is an unallocated space very behind C partition. Otherwise, the Extend Volume will grayed out. Therefore, to increase C drive space from D drive, first of all we should take some space of D partition and make it unallocated. To shrink volume D? NO! It won’t help for the shrunk space is behind D drive not very behind C drive. Thus, the only way we can do is to delete the whole D partition and make it unallocated.

Note: Backup important data on D partition or just transfer them to other drives.

In Disk Management, right click on partition D and select Delete Volume to create unallocated space for increasing partition C. Follow the guidance to finish the operation.

Delete Volume

Then, right click system partition and choose Extend Volume to extend system partition. Still, follow the steps to complete the progress.

More detailed information about how to increase space in c drive using disk management >>

If there are too many data on D drive and you do not want to delete it, is there another way to increase C drive space from D drive?

Allocate Free Space to C Drive from D with AOMEI Partition Assistant

AOMEI Partition Assistant is a third party partition manager which can do not only what DM can do (such as extend partition, shrink partition, delete partition, create partition and format partition), but also what DM cannot do (like move partition, wipe disk, rebuild MBR, split partition, merge partitions, etc.).

1. Right click partition D and select Allocate Free Space.

Allocate Free Space

2. Set how much space you want to allocate form partition D and choose C partition as target.

Allocate Free Space to C Drive from D

3. Preview the result after allocation. If that’s what you want, just click Apply on upper left to carry out the operation.

Allocate Free Space Preview

Tip:If it looks not like what you want, or you want C drive to be larger, you can click Discard behind Apply and do the operations above once more.

Wait until it finishes. Finally, you can enjoy a smooth-running system. The low disk space problem is also solved perfectly. You can also complete “increase c drive space from d drive” task using Extend Partition feature of this software. Anyhow, keep a good habit of using computer can also help in the future. For example, do not install apps or save data on system C drive.