Question

What is the unallocated disk space in windows..??

Answer 1

The disk space which doesn’t belong to any partition is regarded as unallocated space by computer. This refers to no applications are able to write to the space. But it is a logical space on the hard drive so it can be used by putting the system to put files on. In order to make full use of unallocated space, you have to build a new partition with the space or add it to other partition.

Answer 2

this space are free not used in any drive
you can make more drive with this space

when you see black line    this is free space