Why Can't I Expand C Drive If I Have Unallocated Space

Hello, I'm trying to expand my C drive with the unallocated space on the disk. But the Extend Volume greyed out in Disk Management, not allowing me to do so. Why can't I extend C drive when there's unallocated space? Can someone help me? Thanks in advance!

Generally, the reason why you can't extend the C drive with the unallocated space on the disk is that they are not adjacent to each other.

Due to Windows limitations, Disk Management only allows users to extend volume with adjacent unallocated space; that's why the Extend Volume is greyed out in your Disk Management. Thus, the free space must be right next to the target partition if you want to expand the C drive via Disk Management.

Although Windows restricts users from doing so, you can achieve the operation with third-party disk and partition management software like EaseUS Partition Master Professional.

This tool provides a powerful feature called Resize/Move, which can move partitions on the disk to elsewhere and directly adjust the size of a partition. You can follow the instructions here to expand the C drive:

Step 1. Launch EaseUS Partition Master and right-click on the C drive in the Partition Manager tab.

Step 2. Select "Resize/Move," then drag the target partition to move it so that you can make the unallocated space adjacent to the C drive. Or you can drag the dot to add space to the C drive directly.

Step 3. Hit "OK" and execute the task.