When you are unable to make changes to partitions using Disk Management below are partitioning programs you can use EaseUS Partition Master. It allows users to Resize/Move Partition, Extend System Drive, Copy Disk & Partition, Merge Partition, Split Partition, Redistribute Free Space, Convert Dynamic Disk, Partition Recovery and more. The following guide will detail you how to extend a partition with Free EaseUS Partition Master.

Free download EaseUS Partition Master.

If there is no unallocated space behind the partition you want to extend, please follow solution 1. Otherwise, please follow the solution 2.

 Solution 1 - Shrink D drive and extend C drive.

1. Free download EaseUS Partition Master and install it. After that, launch EaseUS Partition Master.

2. Select D: drive, right click D: and select "Resize/Move partition".

3. Position the mouse pointer on the left partition handle to shrink D: drive.

4. Click OK. Then there is unallocated space on the right side of C: drive.

5. Repeat step 2 and 3. Position the mouse pointer on the right handle of C: drive to extend it.

6. Click Apply.

Solution 2 - Directly extend C drive when there is unallocated space behind it.

1. Launch EaseUS Partition Master.

2. Right click C: drive and select "Resize/Move partition".

3. Position the mouse pointer on the right partition handle. Drag the handle to rightwards to extend C drive and click Ok.

4. Click Apply.