This article explains why Extend Volume is disabled for system C drive in Disk Management, and the full solution to fix Extend Volume option disabled issue for Windows PC and Server.
Applies to: Windows 10, Windows 8/8.1, Windows 7, Windows Vista, Windows Server 2019, Windows Server 2012 R2, Windows Server 2008 R2, Windows Small Business Server (SBS) 2011/2008.
Extend Volume option is disabled in Disk Management
Most of Windows computer users encountered the low disk space issue, especially for system C drive. Windows Updates, programs and many other types of files write into C drive every day, so it becomes full sooner or later.
If it happens in Windows XP or Windows Server 2003, you have to back up everything, delete and recreate partitions, finally restore. Maybe Microsoft found this defect, so it added new Shrink and Extend volume functions in native Disk Management tool from Windows Vista and Server 2008. It is a good start but most of the disk space issue still cannot be fixed.
When C drive is running out of space, it cannot be better if you can shrink D to expand C drive, right? Unfortunately, after shrinking volume D Extend Volume option is disabled for C drive. This article explains all possible reasons and how to fix this issue when Extend Volume is disabled in Disk Management for Windows laptop, desktop and server.
Reasons why Extend Volume is disabled for system C drive
Reason 1. No adjacent Unallocated space
A 300GB hard disk cannot be increased to 500GB (except VMware/Hyper-V virtual disk), so before extending a partition you must delete or shrink other one to get some Unallocated space. As the name, this space is not allocated to any drive. In Windows XP Disk Management, Unallocated space can only be used to create new drives. In Windows 7 and subsequent versions, it can be added into other drive without losing data.
To get Unallocated space, you may either delete or shrink a drive. After deleting a volume, all its disk space will be converted to Unallocated but you'll lose all files in it. By shrinking a volume, only part of free unused space will be converted to Unallocated and you won't lose files.
Obviously, it's better to get Unallocated space by shrinking a volume. The problem is that you can't extend a volume after shrinking other one with Disk Management. As the screen shot shows, Extend Volume is disabled for C: and E: drive after shrinking D.
This is because:
- Shrink Volume function can only make Unallocated space on the right while shrinking any partition.
- Extend Volume function can only combine Unallocated space to the contiguous partition on the left.
This is the most common issue encountered by Windows computer users.
To solve this problem:
You should run NIUBI Partition Editor to merge Unallocated space to the right contiguous drive E, or move drive D towards right and then combine Unallocated space to system C: drive.
Reason 2. Restriction between Primary and Logical partition
Some people tried to delete a partition to get adjacent Unallocated space. It works when you extend partition in GPT style disk, but in MBR disk, it depends. If the right contiguous partition D is Logical, you still cannot extend C drive in Disk Management after deleting D.
As you see in the screenshot, Extend Volume is disabled for D: drive after deleting the right contiguous partition E.
This is because:
In MBR style hard disk, Free space deleted from a Logical partition can't be extended to any Primary partition. Unallocated space deleted from Primary partition can't be extended to any Logical drives.
Therefore, in MBR disk, the partitions that you want to delete and extend must be the same Primary partition or Logical drive.
To solve this problem, you just need to run NIUBI Partition Editor to merge the adjacent free space.
In MBR disk there are only 4 entries in Master Boot Record sector, so you can only create 4 Primary partitions or 3 Primary plus an Extended partition. Unlike Primary partition that works as independent unit, Logical drives are part of the Extended partition, this is the reason why it is shown as Free after deleting.
Why Extend Volume is disabled for D or other data volume
Reason 3. Only NTFS is supported
Extend Volume function only support extending NTFS partition so you cannot extend FAT32 or any other types of partition even if there is adjacent Unallocated space on the right side.
As you see in the screenshot, there's 20GB Unallocated space next to D: drive, but because it is a FAT32 partition, so Extend Volume is disabled.
In most of Windows computers, system C drive is formatted with NTFS, so this issue is common for data drives.
To solve this problem, simply merge this Unallocated space to D drive with NIUBI Partition Editor by 1 step.
Reason 4. Limitation of MBR disk
Nowadays, hard disks are much larger and it is very common to use 2TB to 4TB disk for personal computers. To a server, it is common to use over 10TB RAID array via several large disks. But if you initialized the disk as MBR, you'll encounter another problem that you can only use 2TB disk space.
As the screen shot shows, drive H is formatted as NTFS and there is right contiguous Unallocated space, but Extend Volume is still disabled. If you right click this Unallocated space in Disk Management, all options are unavailable.
To solve this problem, you need to convert disk from MBR to GPT and then extend partition with Unallocated space.
What to do when Extend Volume doesn't work
Download NIUBI Partition Editor, you'll see all disks (physical and RAID virtual) with partition structure, follow the corresponding solution according to your own disk partition configuration.
Solution 1: Move non-adjacent Unallocated space
When Extend Volume is disabled for C drive because Unallocated space is non-adjacent, follow the steps below:
- Run NIUBI Partition Editor, right click drive D and select "Resize/Move Volume", drag the middle towards right in the pop-up window.
- Right click C: drive and select "Resize/Move Volume" again, drag right border towards right to combine Unallocated space.
- Click Apply on top left to execute. (All operations before this step only works in virtual mode.)
Solution 2: Merge adjacent Unallocated space
When there's adjacent Unallocated space, Extend Volume is disabled because of non-supported FAT32 partition or the restriction between Primary and Logical partition, follow the steps below:
- Run NIUBI Partition Editor, right click the adjacent partition and select "Resize/Move Volume".
- Drag the border towards other side to combine Unallocated space in the pop-up window.
- Click Apply on top left to execute.
Solution 3: Convert 2TB+ MBR disk to GPT
When Extend Volume option is disabled on a larger than 2TB disk, follow the steps below:
- Run NIUBI Partition Editor, right click front of this disk and select "Convert to GPT Disk".
- Run "Resize/Move Volume" function and combine Unallocated space to the partition(s) that you want to expand.
Better than other tools, NIUBI Partition Editor has innovative technologies to protect system and data such as:
- Virtual Mode - all operations will be listed as pending for preview, real disk partitions won't be changed until click Apply to confirm.
- Cancel-at-well - if you applied incorrect operations, it doesn't matter, you can cancel the ongoing operations without causing damage.
- 1-Second Rollback - if anything goes wrong while resizing partition, it automatically reverts computer to original status in a flash. If it happens, nothing will be changed.
It is also 30% to 300% faster because of the advanced file-moving algorithm, it's very useful when you move partition with large amount of files.