Windows 10 Disk Management inherited Shrink Volume and Extend Volume functions from previous version. Shrink Volume can decrease the size of both system C drive and data volumes. Extend Volume can increase size of a drive when there is adjacent Unallocated space. Both functions are safe to change partition size in Windows 10 (32 & 64 bit).
However, if you want to extend a volume by shrinking another one, it is impossible.
Because of many restrictions, Windows Disk Management is not the best tool to resize partitioned drives. Professional partition software is much more powerful.
How to decrease partition size:
This drive will be shrank within a short time in most cases.
Restrictions of Shrink Volume function:
How to increase partition size:
Only when your disk drive configuration meet the requirements, Extend Volume is workable to increase partition size.
To increase volume size:
Comparing with Windows 10 Disk Management, NIUBI Partition Editor has advantages while resizing partition, for example:
How to change partition size in Windows 10 with NIUBI:
Download NIUBI Partition Editor and you'll see all disk partitions with structure and other information. In my test computer, there are drive C, D, E and system reserved partitions.
There are two options when decrease partition size, right click this partition (here is D:) and select "Resize/Move Volume".
Option 1: drag left border towards right in the pop-up window,
Then Unallocated space will be produced on the left side.
When there is adjacent Unallocated space, you can combine it to other partitions easily.
To increase size of partition C:
Right click C and select "Resize/Move Volume" again, drag right border rightwards to combine Unallocated space.
To increase size of partition E:
Right click E and select "Resize/Move Volume" again, drag left border leftwards to combine Unallocated space.
If you want to decrease E to increase C, follow Option 1 to make Unallocated space on the left side of E. Before adding Unallocated into C drive, there is an additional step to move Unallocated space to left side of D.
To do this, right click drive D and select "Resize/Move Volume", drag middle position towards right in the pop-up window.
There is potential system and data damage risk while change partition size for Windows 10 computers. So you'd better back up first and use safe partitioning software. Better than other software, NIUBI Partition Editor provides powerful 1 Second Rollback, Virtual Mode and Cancel-at-well technologies to protect system and data.
Besides changing partition size, it helps you do many other operations such as: merge, convert, defrag, copy, hide, wipe and scan partition. Initialize, convert, set read-only attribute to disk, etc.