This article explains why Extend Volume greyed out in Windows Server 2016 Disk Management and how to fix Extend Volume is disabled for C or D drive.
Windows Server 2016 native Disk Management has Shrink Volume and Extend Volume functions to change size of allocated partition without losing data. However, many people feedback that Extend Volume greyed out in Disk Management. The typical example is that Extend Volume is disabled for C drive after shrinking partition D. This article explains all probable reasons why Extend Volume greyed out in Windows Server 2016 Disk Management and what to do when Extend Volume is disabled for C or D drive.
Why Extend Volume greyed out in Windows Server 2016
There are two common disk types in Windows server - GPT and MBR, there are two common files system in a single partition - NTFS and FAT32. If you use GPT hard disk, there are 2 common reasons why Extend Volume option is grayed out. If you use MBR disk, there are 2 additional reasons.
Reason 1. No adjacent Unallocated space (both on MBR & GPT disk)
A 256GB physical hard disk cannot be increased to 512GB, so before extending a partition, you must shrink or delete another one to get Unallocated space. By deleting a partition, all its disk space will be converted to Unallocated, but the files will be lost. By shrinking a drive, part of the unused space will be converted to Unallocated and you won't lose files.
If you did not shrink or delete other volume to get available Unallocated space, of course Extend Volume is grayed out.
Many server administrators know about this, they did shrink drive D before extending C: drive, but Extend Volume is still disabled after that.
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. Therefore, Extend Volume is disabled for C: and E: drive after shrinking D.
Reason 2. Only NTFS is supported (both on MBR & GPT disk)
Extend Volume function only support extending NTFS and RAW (no file system) partition, so another common FAT32 and any other types of partition can't be extended even if there is adjacent Unallocated space on the right side.
To show you this limitation, I formatted drive D to FAT32. As you see in the screenshot, there's 20GB Unallocated space next to it, but because it is a FAT32 partition, Extend Volume is disabled for D drive.
In most of Windows servers, system C drive is formatted with NTFS, so this issue is just common for data drives.
Reason 3. Restriction between Primary and Logical partition (on MBR disk)
Because it doesn't work by shrinking a volume, some people are wondering whether it works by deleting partition instead. If on GPT disk, yes, but if you use MBR disk, it depends.
In GPT disk, all partitions are Primary, but in MBR disk, there may be Primary and Logical partitions. If the type of partition that you want to delete is different, you cannot extend other volume after deleting.
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 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.
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.
Reason 4. Limitation of MBR disk (on MBR disk)
Nowadays, hard disks are much cheaper and larger, so it is very common to use 2TB to 4TB single disk or over 10TB RAID array. If you initialized the disk as MBR, you can only use 2TB disk space in Disk Management.
As the screen shot shows, drive H is formatted as NTFS and there is right contiguous Unallocated space, but Extend Volume is grayed out.
To use full disk space, you need to convert disk from MBR to GPT and then extend partition with Unallocated space on the end of this disk.
What to do when Extend Volume is disabled in Server 2016
Open Disk Management and find out your server disk configuration, then follow the corresponding method below according to your own disk partition structure.
Solution 1: Move partition and Unallocated space
How to fix Extend Volume greyed out in Windows Server 2016 after shrinking drive D:
- Download 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: Simply merge Unallocated space
How to fix Extend Volume is disabled in Windows Server 2016 because of non-supported FAT32 partition or the restriction between Primary and Logical partition:
- 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 MBR disk to GPT
When Extend Volume option greyed out 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.
Take care of system and data
Unlike read-only program, partitioning software will modify the parameters of associated disk, partition and files. Therefore, there's potential system damage and data loss risk especially when you shrinking and moving partitions. Remember to back up before any operations to a server, it is also important to run safe partition software.
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 server to original status in a flash. If it happens, your server could back online rapidly without damage.
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. Besides help fix Extend Volume greyed out issue in Windows Server 2016, it helps merge, copy, convert, hide, wipe partition, scan bad sectors and much more.