How to increase virtual machine disk size in VMware

To increase a virtual machine disk size in VMware, power off the VM, open its settings, select the hard disk, set a larger size, then extend the partition inside the guest operating system.

This guide covers VMware Workstation Pro, the vSphere Client, ESXi command-line tools, and the partition steps for Windows and Linux guests, plus fixes when the expand option is greyed out.

Increase the size of VM disk (VMDK) in VMware

In VMware Workstation Pro, the Expand utility grows the VMDK file. It does not touch the partitions or file systems inside it, so the guest step later in this guide is still required.

  1. Shut down the guest operating system and power off the virtual machine.
  2. Delete every snapshot of the virtual machine, because a disk with snapshots cannot be expanded.
  3. Select the virtual machine in the library, then select VM > Settings.
  4. On the Hardware tab, select the virtual hard disk you want to expand.
  5. Select Utilities > Expand.
  6. Enter the new maximum disk size. Workstation Pro accepts a size between 0.001 GB and 8192 GB.
  7. Select Expand, then select OK when the process completes.
  8. Power on the virtual machine and extend the partition in the guest operating system.

The added space shows up in the guest as unallocated space at the end of the disk until you extend a partition into it.

How to increase virtual machine disk size in VMware
In Workstation Pro, Utilities > Expand sets a new maximum size between 0.001 GB and 8192 GB for the virtual disk. (Image: techdocs.broadcom.com)

VMware disk expand options for Workstation, ESXi and vSphere

Your setup Use this Why
VMware Workstation Pro or Player on a PC VM > Settings > Utilities > Expand Built into the disk settings, no command line needed
Workstation, scripting or no GUI access vmware-vdiskmanager -x Resizes the VMDK from a command prompt in the install folder
ESXi host or vCenter Server vSphere Client or ESXi host client Edit Settings Supports hot extend on PVSCSI disks from vSphere 7.0 and NVMe disks from vSphere 8.0.1
Clustered (shared) disks on ESXi vmkfstools -X in the ESXi shell VMware states clustered disks cannot be expanded through the vSphere Client
You cannot expand the existing disk Add a second virtual hard disk VMware lists this as the alternative to expanding

Requirements to expand a VMware virtual disk

Requirement Details
No snapshots Remove every snapshot first. If Disk File in Edit Settings reads like VM-000001.vmdk, the VM is running on snapshot disks and the VMDK cannot be extended.
Powered off (most cases) Workstation needs the VM powered off. On vSphere the VM must be off except for PVSCSI hot extend (vSphere 7.0 and later) and NVMe hot extend (vSphere 8.0.1 and later).
Not a linked clone In Workstation the VM cannot be a linked clone or the parent of one. "Clone of:" or "Snapshot: Snapshot for" on the summary page shows it is.
Disk not mapped or mounted Workstation cannot expand a virtual disk while it is mapped or mounted on the host.
vSphere privileges Modify device settings, Extend virtual disk and Allocate space on the datastore.
SCSI controller on vSphere IDE disks cannot be expanded in the vSphere Client.
Backup VMware recommends a valid backup of the VM before resizing any disk.

Increase VM disk size in the vSphere Client or ESXi host client

The same Edit Settings dialog works in vCenter's vSphere Client and in the ESXi host client on a standalone host.

  1. Delete or consolidate the VM's snapshots, then power off the VM unless the disk is on a PVSCSI or NVMe controller that supports hot extend.
  2. Right-click the virtual machine in the inventory and select Edit Settings.
  3. On the Virtual Hardware tab, find Hard disk 1 (or the disk you want to grow).
  4. Type the new size in the size box next to the disk and keep the unit as GB.
  5. Check Maximum Size under the expanded disk entry to confirm the datastore has room.
  6. Select OK to apply the change.
  7. Extend the partition inside the guest operating system.

Extending a disk briefly stuns the VM, and VMware notes the stun time is longer for Eager Zeroed Thick disks. Large disks over 2 TB need a VMFS5 or later, NFS or vSAN datastore, and the maximum is 62 TB.

Increase VM disk size in vSphere Client from Edit Settings Virtual Hardware tab
Expand Hard disk on the Virtual Hardware tab; growing the disk causes a short stun time, longer for Eager Zeroed Thick disks. (Image: techdocs.broadcom.com)

Expand a VMDK with vmware-vdiskmanager in Workstation

Virtual Disk Manager (vmware-vdiskmanager.exe) ships in the VMware Workstation program files folder. Open a command prompt, change to that folder, power off the VM and remove its snapshots first.

vmware-vdiskmanager -x 100Gb "D:\VMs\Windows 11\Windows 11.vmdk"

-x expands the virtual disk to the size you give. Replace 100Gb with the size you want (Kb and Mb units also work) and the path with the full path to your VMDK.

You should see: The tool reports that the disk was expanded. The guest still needs its partition extended before the space is usable.

Expand VMDK with vmware-vdiskmanager, the Workstation Virtual Disk Manager utility
vmware-vdiskmanager.exe sits in the Workstation program files folder and can enlarge a disk beyond the size it was created with. (Image: techdocs.broadcom.com)

Extend a VMDK with vmkfstools on ESXi

Use this route for clustered disks, which VMware says cannot be expanded through the vSphere Client. Run it in the ESXi shell from the VM's datastore folder.

vmkfstools -X 6G -d eagerzeroedthick vm.vmdk

-X extends the virtual disk to the size value (6G in VMware's example) and -d eagerzeroedthick keeps the format clustered disks need. Use the descriptor file name, not the file ending in -flat or -s0.

You should see: The command returns without an error and Edit Settings shows the new disk size.

Extend VMDK with vmkfstools -X on ESXi, with the vSphere Client steps
Run vmkfstools -X with the new size and the -d eagerzeroedthick format; a greyed-out size box usually means snapshots exist. (Image: knowledge.broadcom.com)

Extend a partition in a Windows virtual machine

Disk Management can extend a volume only into unallocated space that sits immediately after it on the same disk, and only on NTFS or ReFS volumes.

  1. Sign in to the Windows guest with an administrator account.
  2. Right-click Start and select Disk Management.
  3. Select Action > Rescan Disks so Windows reads the new disk size without a restart.
  4. Right-click the volume next to the Unallocated space, usually C:, and select Extend Volume.
  5. Select Next in the Extend Volume Wizard.
  6. Leave the amount at Maximum available, or enter a smaller amount, then select Next.
  7. Select Finish.
Extend partition in Windows VM: Disk Management showing unallocated space after C:
After expanding the VMDK, the new space appears as an Unallocated block right after C:, ready for Extend Volume. (Image: Microsoft)

Extend the C drive in a VMware Windows VM with PowerShell

Open Windows PowerShell as administrator in the guest. Change C to the drive letter you want to grow.

$size = (Get-PartitionSupportedSize -DriveLetter C)
Resize-Partition -DriveLetter C -Size $size.SizeMax

Get-PartitionSupportedSize reads the largest size the partition can reach, and Resize-Partition grows it to that maximum.

You should see: The command returns no error, and Get-Volume -DriveLetter C shows the larger size.

DiskPart works too: run diskpart, then list volume, select volume <number> and extend. Without a size= value, extend uses all contiguous free space, and NTFS grows with the partition.

How to extend partition in Linux virtual machine?

Check the layout with lsblk first. The steps below assume the root file system is partition 1 on /dev/sda; adjust the device and number to match your VM.

  1. Restart the Linux VM after expanding the VMDK, or rescan the disk, so the kernel sees the larger /dev/sda.
  2. Run sudo growpart /dev/sda 1 to grow partition 1 into the free space at the end of the disk. Add -N first for a dry run.
  3. If the partition is an LVM physical volume, run sudo pvresize /dev/sda1, then sudo lvextend -l +100%FREE -r <vg>/<lv> to grow the logical volume and its file system together.
  4. For an ext4 partition without LVM, run sudo resize2fs /dev/sda1. With no size given, it fills the partition and works on a mounted file system.
  5. For an XFS file system without LVM, run sudo xfs_growfs -d /. XFS must be mounted to grow.
  6. Run df -h to confirm the file system shows the new size.

growpart exits with code 1 when there is no free space to claim, which usually means the VMDK expand did not apply or the kernel has not reread the disk.

Extend partition in Linux virtual machine with growpart synopsis and options
growpart takes the disk and partition number, for example /dev/sda 1; add -N for a dry run first. (Image: manpages.ubuntu.com)

Check the new VMware disk size in the guest OS

  1. In Workstation, open VM > Settings and confirm the hard disk shows the new Maximum size. In vSphere, open Edit Settings and check the disk size.
  2. In a Windows guest, open Disk Management and confirm no Unallocated block remains after the volume you extended.
  3. Open File Explorer > This PC and check the drive's total size.
  4. In a Linux guest, run lsblk to see the disk and partition size, then df -h to confirm the file system matches.

VMware expand disk greyed out and other resize errors

Expand or the disk size box is greyed out

The VM has snapshots, is powered on, is a linked clone, or uses an IDE disk on vSphere.

  1. Delete all snapshots and wait for consolidation to finish.
  2. Power off the VM unless its controller supports hot extend.
  3. In vSphere, check the controller type; IDE disks cannot be expanded in the vSphere Client.
  4. Check Maximum Size to confirm the datastore has enough free space.

Extend Volume is greyed out in Windows

Another partition sits between the volume and the unallocated space, or the volume is not NTFS or ReFS.

  1. Open Disk Management as administrator and select Action > Rescan Disks.
  2. Confirm the Unallocated block is directly to the right of the volume.
  3. If another volume is in between, create a new volume in the unallocated space instead of extending.
  4. For a disk over 2 TB, make sure it uses the GPT partition style.

Windows shows the old size after DiskPart reports success

The system page file is on the volume being extended.

  1. Move the page file to another partition in the guest.
  2. Restart the guest, then run the extend again.

"Failed to open the disk … A file was not found (0x1900000004)"

The VM did not power on cleanly or still has snapshot files.

  1. Confirm the VM powered on successfully before the resize.
  2. Remove all snapshots and run the expand again.
  3. If the error persists, contact VMware support through Broadcom.

Linux still shows the old size after growpart

The file system was not grown after the partition, or the LVM physical volume was not resized.

  1. Run lsblk to see whether the partition or the file system is still small.
  2. Run pvresize and lvextend -r for LVM, or resize2fs or xfs_growfs for plain partitions.
  3. Run df -h again.
Extend Volume greyed out in Disk Management with a recovery partition in between
Extend Volume stays grey when another partition sits between C: and the unallocated space, as the recovery partition does here. (Image: Microsoft Q&A)

VMware virtual disk resize FAQ

Can I increase a VMware disk size without losing data?

Yes. Expanding a VMDK does not change the data, partitions or file systems inside it. Extending an NTFS partition in Windows also keeps its data. VMware still recommends a backup before you resize.

Why is the new space not showing in my virtual machine?

The expand only enlarges the virtual disk file. The guest sees the extra capacity as unallocated space until you extend a partition into it with Disk Management, PowerShell, growpart or LVM tools.

Can I expand a VMware disk with snapshots?

No. VMware requires all snapshots to be removed before a virtual disk can be expanded, in both Workstation and vSphere. Delete or consolidate the snapshots, then expand the disk.

Can I increase a VMDK while the VM is running?

On vSphere, yes for PVSCSI disks from vSphere 7.0 and NVMe disks from vSphere 8.0.1. Other controllers, and VMware Workstation Pro, need the virtual machine powered off.

What is the maximum virtual disk size in VMware?

VMware Workstation Pro accepts a virtual disk size up to 8192 GB. On vSphere, large capacity virtual disks can reach 62 TB on VMFS5 or later, NFS or vSAN datastores.

Can I shrink a VMware virtual disk?

The Expand utility only grows a disk. To reclaim host space instead, Virtual Disk Manager can convert a preallocated disk into a growable one that is still large enough for all its data.

Should I expand the disk or add a new one?

Expand the disk when the system drive needs space. Add a second virtual hard disk when snapshots or linked clones block the expand, or when you want data kept on a separate drive.

Philip Celasco

Philip is a Texas-based technology writer and IT administrator at Techdows.com with more than 10 years of experience creating practical content for everyday users and professionals. He specializes in web browsers, particularly Chromium-based platforms such as Google Chrome, Microsoft Edge, Brave, and Opera. Through his work as an IT administrator, Philip has hands-on experience managing devices, configuring browser policies, troubleshooting software and network issues, and helping people resolve problems that affect productivity and security. His articles are based on practical testing and real-world technical experience. He covers browser settings, extensions, performance problems, privacy controls, security features, and Windows troubleshooting. Outside work, Philip enjoys the quieter side of life in Texas and stepping away from the screen when he can. He has two kids, two cats and loves to play golf with his mother during the weekends.

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