This post offers enough information on Windows 8 Disk Management, including how to open Windows 8 Disk Management, how to resize disk partition via this built-in Windows 8 disk manager.
The Windows 8 Disk Management is a built-in system utility that allows you to perform some basic and advanced disk partition management tasks. It has the features as follows.
Basic features: ▸Create a partition, delete a partition or format a partition. ▸Change a drive letter or assign a new drive letter to a partition. ▸Initialize disk to MBR or GPT. ▸Mark a partition as Active. ▸Check the partition property.
Advanced features: ▸ Extend a volume and shrink a volume. ▸ Convert a basic disk to a dynamic disk ▸ Convert an empty MBR disk to GPT disk, and vise versa. ▸Convert an empty dynamic disk to a basic disk.
To open Windows 8 or 8.1 Disk Management, you can apply the following two methods, which are the most widely used by users.
Open Disk Management from CMD: Start "Run" by pressing "Windows Logo Key"+ [R], input "diskmgmt.msc" in the text box, and click "OK". (See from the screenshot below.) Disk Management in Windows 8 will start right away.
Or, you can right-click “Computer”, select Manage->Disk Management. Then, you can see the basic situation of your disks.
Windows 8 Disk Management has the functions “Shrink Volume” and “Extend Volume”. You can shrink or extend a partition by right-clicking the target partition, and selecting "Shrink Volume" or "Extend Volume", then input the number of space you want to shrink or extend.
Sometimes, when you try to enlarge a volume capacity with the “Extend Volume” feature, you might find it is greyed out and cannot be clickable. Why? The most common reason is that there is no unallocated space right behind the target partition and Disk Management ony supports extending a partition followed by an adjacent unallocated space. If there is such space, and the “Extend Volume” is still greyed out, it might because the partition is formatted with FAT32 file system and the Disk Management can only extend a RAW or NTFS volume.
Besides, the Windows 8 Disk Manager also has some limitations when shrinking a volume. It also work on the RAW and NTFS partition only. Besides, if there are some unmovable files like page file and hibernation file located in the middle of the target volume, you cannot shrink a volume as more as you need.
As you can see from above, Windows 8 Disk Management built-in does have some limitations. So getting an alternative to Windows Disk Management is necessary, especially when you cannot extend a volume due to its restrictions. Here, you can try the third-party free partition manager: AOMEI Partition Assistant Standard. It makes up the deficiencies of Disk Management. The following table offers more details.
| Features | AOMEI Partition Assistant | Windows 8 Disk Management |
| Create, delete, format partitions, change drive letter, set active | √ | √ |
| Extend/Shrink NTFS partition | √ | √ |
| Hide, label, check partitions | √ | √ |
| Extend/Shrink FAT partition | √ | ╳ |
| Merge partitions | √ | ╳ |
| Move partition | √ | ╳ |
| Allocate free space | √ | ╳ |
| Copy disk & partition | √ | ╳ |
| Convert FAT to NTFS | √ | √ |
| Convert primary to logical and vice versa | √ | √ |
| Wipe disk, partition, unallocated space | √ | √ |
| Resize dynamic disk, BitLocker partition | √ | √ |
The free AOMEI Partition Assistant Standard can shrink or extend both FAT32 and NTFS partition. When the unallocated space is not right behind the partition you want to extend, you can use the “Merge Partitions” feature. Besides, its “Shrink Volume” allows you to easily shrink volume even if there are unmovable files. The picture below is the main interface of AOMEI Partition Assistant. You can accomplish any task simply.
Now download the freeware and have a try. AOMEI Partition Assistant is also fully compatible all editions of Windows 7, Windows 8.1, Windows 10 and Windows XP/Vista.