How to Reduce C Drive Spaces in Windows 10 Without Formatting

This article describes how to reduce C drive space in windows 10 without formatting, including creating new partitions from C drive and adding unallocated spaces to D drive.

Way 1. Reduce C drive spaces, and create new volumes

A new laptop generally comes with only one partition, the C drive. (In fact, there are two more invisible partitions—Recovery partition and EFI (Extensible Firmware Interface) System partition.) That's because manufacturers are unable to decide how many partitions a hard disk should be when facing extensively various demands from users.

What's more, if they set an unallocated partition, which can't be used directly, it may also cause a misunderstanding about disk sizes. Therefore, each computer with only one partition is the best choice for manufacturers, leaving users to personalize the number of partitions.

If you have no idea about the size of the C drive and other partitions, please see Best Partition Size of 500GB Hard Disk for Windows 7, 8 and 10 and Best Partition Size for 1TB Hard Drive in Windows.

Now we begin to reduce C drive spaces and create new partitions.

1. Run Disk Management: Right click "My Computer" -> Manage ->Storage -> Disk Management.

2. Right-click C drive and select "Shrink Volume...".

3. Enter the amount of space you want to reduce from the C drive. The amount of "Total size after shrink in MB" is the size of c drive after shrink. Generally, the recommended size for a C drive is about 150GB.

Now, we have already created an unallocated space and we can create new partition from it.

4. Right-click the unallocated partition, and select "New Simple Volume". Now, the only thing you need to do is to follow the wizard to create one or more partitions.

Way 2. Shrink C drive volume, and add unallocated spaces to D drive

Notice: The unallocated space partitioned from the C drive cannot be merged with the D drive in the picture below. Of course, the unallocated space released from C Volume is available to create new partitions.

If you want to merge the unallocated space to the D drive, you should backup data on the D drive, delete it, and then use the unallocated space to create it again. Follow the steps below:

1. Reduce the spaces of c drive.

1.1 Right-click "My Computer" -> Manage ->Storage -> Disk Management.

1.2 Right-click C drive, choose "Shrink Volume...", and then enter the amount of space you want to reduce from C drive.

2. Backup data. You can copy all data on the D drive to another drive. Or use software to backup files, see https://www.shareus.com/software/clonego/.

3. Delete D drive. Right-click D drive, choose "Delete Volume..." to delete it.

4. Right-click the unallocated space, and choose "New Simple Volume..." to create D drive again. After creating a D drive, you can copy data back to it, and you computer will run as before.