What’s unallocated space for?
After a period of time, you may find that your computer runs slowly or cannot react
to commands immediately, or even your screen becomes gray so that it cannot work at
all. Those problems may be caused by the same reason that your system partition is
out of space. This can be proved when you look into Computer, and
you will have no surprise to see that system partition which usually is assigned
with drive letter C shows red bar due to low drive space, while other partitions may
show green bar with enough drive space. In order to solve the problem, you could
extend C drive with unallocated space. But how to create unallocated space when
there is none?
Create unallocated space with Disk Management
Windows inbuilt Disk Management is able to create unallocated space and you can
achieve this by two different ways - either shrink a partition or delete a
Method 1: Shrink Partition
1. Right click the partition you want to shrink (here is I: drive), and click “Shrink
2. Type the number of size you want to get as unallocated space.
3. Now you get the unallocated space.
As you can see, there is an unallocated space created behind I: drive. But, in this
situation, you cannot use Disk Management to extend C drive with the unallocated
space, because DM asks the unallocated space must be adjacent and behind the
partition which is needed to be extended. Therefore, you should use a third party
software to finish the rest job, such as AOMEI Partition Assistant which is able to
partitions, or you can change to create unallocated space by deleting the
partition next behind C drive.
Method 2: Delete Partition
1. Right click I: drive, and select “Delete Volume”. (This will delete everything on
the partition, so please backup before
2. Now you have created the unallocated space. Then you can use DM to extend C:
drive with it.
Maybe for some of you, deleting partition will be treated as a risk of losing data.
Then, there is an easier and safer way to extend your C drive without
unallocated space, that is, allocate free space from one partition to C drive via
AOMEI Partition Assistant.
AOMEI Partition Assistant is a professional partition manager, it not only provides
with resize/move, merge, split, copy, create, delete, format, delete partition and
all other basic partition features, but also supports some advanced features like
make bootable media, convert NTFS and FAT32, create Windows To Go, and of course
allocate free space etc. Next, we show you how to allocate free space from your I:
drive to C: drive.
1. Launch AOMEI Partition
Assistant Professional Edition.
2. Right click D drive, and select “Allocate Free Space”.
3. In pop-out window, specify the free space to be allocated and the destination
partition that the free space will be added to.
4. Now you can preview the result, and remember to click “Apply”.
What’s your purpose to create unallocated space? If you do want to use an unallocated
space to extend partition, then using AOMEI Partition Assistant to allocate free
space is the best option as you can know.