Unallocated space is the space not used by any partition. In Disk Management, unallocated space is shown as a black bar (image attached). If you see no unallocated space, you can get some by right-clicking and shrinking any primary partition. Since it is not taken up by any partition, it can be used to create a new partition on the drive. Besides, you can also use the unallocated space to extend any partition on the same basic disk in the following situations:
• Your computer is running on low disk space.
• You want to save more files to a partition but there is not enough free space.
• You need to upgrade Windows 7/8 to Windows 10 but Windows say “We couldn’t update the system reserved partition”.
If you are facing such problems, how can you use the unallocated space to extend volume? Next, we will show you the details.
In fact, it is rather easy to add unallocated space Windows 10 if you have professional disk partition manager to help you. MiniTool Partition Wizard, the best partition magic alternative, is able to add unallocated space to any partition that lies on the same drive within only several clicks. Here we just take how to add unallocated space to C drive Windows 10 for instance.
Kind remind: You can also use Windows built-in Disk Management to add unallocated space. Right-click This PC > Manage > Disk Management. If there is unallocated space next to the partition you want to extend, then Disk Management is helpful. Please note that sometimes when you will find that the “Extend Volume is greyed out”. If Windows 10 cannot extend volume for you, you have better use MiniTool Partition Wizard to help you.
1. Launch MiniTool Partition Wizard to the main interface. Then select the partition you want o extend and choose “Extend Partition” from the action panel.
2. In the pop-up window, drop down the list and choose the unallocated space to take some space. Besides, you can drag the slider to decide how much unallocated space you need. Click OK to continue.
3. Finally, press “Apply” on the toolbar.
Note: We also recommend using MiniTool Partition Wizard Bootable to extend system partition in case that some accident can happen.
So the bottom line here is that unallocated space is very useful to extend partition on the same drive. You can choose either Disk Management or MiniTool Partition Wizard to help you. In short, MiniTool Partition Wizard is a better choice and can help you add unallocated space when you see “Extend Volume” greyed out. It’s all depends on you.