Extend Volume of Disk Management can only extend system partition or any data drive when there is adjacent Unallocated space, furthermore, Unallocated space must be on the right side. As the name, Unallocated space is not allocated to any partition.
The size of a hard disk is fixed, so before extending a partition, there must be Unallocated space. Generally speaking, there are 2 common reasons why unable to extend system drive in Windows 10, I'll introduce one by one. In this article, I'll explain why you are unable to extend system drive with Windows 10 DM and the easy solution to fix this issue. However, many users feedback that they cannot extend system volume in Windows 10 Disk Management. Windows 10 Disk Management has built-in Extend Volume function which can be used to extend system drive or any data partitions. It is very common that the system partition runs out of space, no matter you use desktop or laptop, use SSD or mechanical hard disk for Operating System.
