VMware ESXi and vSphere Cluster Management

Add an Existing Virtual Hard Disk to a VMware Workstation Player Virtual Machine

Learn how to attach an existing VMDK virtual disk to a VMware Workstation Player VM, select a compatible controller, verify it in the guest OS, and avoid data loss.

VMware Workstation Player can attach an existing virtual hard disk to an existing virtual machine as an additional disk. This is useful when moving a data disk between virtual machines, inspecting files from a failed VM, or reusing a previously created disk.

An existing virtual disk is different from a new blank disk. Creating a new disk produces empty storage. Attaching an existing disk connects VMware to a disk file that already contains partitions, filesystems, and possibly data.

This procedure changes the target VM's virtual hardware configuration. It does not change the contents of the guest operating system disk by itself. However, once the guest OS starts, it may write metadata to the attached disk, so make a backup copy before working with important data.

Prerequisites and safety checks

Before changing the VM hardware, complete these checks:

  • Power off the target virtual machine completely. Do not change its hardware while it is running or suspended.
  • Make sure the disk file is available on the host computer or at a location that VMware can access.
  • Identify the correct VMware disk descriptor, normally a file ending in .vmdk.
  • Back up important disk files. For recovery work, attach a copy rather than the only original whenever possible.
  • Confirm that another running VM is not using the disk.
  • Do not attach one writable disk simultaneously to multiple VMs unless the guest workload and storage design explicitly support shared-disk access.
  • Check that the target VM has room for another virtual device and that it has a suitable storage controller.

Important terms

A virtual hard disk is a file or group of files that represents a hard drive for a virtual machine. VMDK is the VMware virtual disk format commonly used by Workstation Player.

The guest operating system is the OS running inside the VM. It must understand both the disk's partitioning scheme and its filesystem before it can read the stored files.

A disk controller is the virtual storage interface used by the guest OS to communicate with a disk. Common choices include:

  • IDE: An older interface that may be useful for compatibility.
  • SCSI: A common controller family in VMware guest configurations.
  • SATA: A virtual interface modeled after Serial ATA hardware.
  • NVMe: A high-performance interface available only in supported VM and guest configurations.

Not every Workstation Player version or guest OS presents every controller type. If you are uncertain, retain a compatible default choice, especially when attaching a non-boot data disk.

Attach the existing disk in VMware Workstation Player

1. Select the target virtual machine

Open VMware Workstation Player and select the virtual machine that should receive the disk in the library. Verify the VM name carefully, particularly if several similar test or recovery VMs exist.

2. Open Virtual Machine Settings

Open the VM management menu and choose the virtual machine settings option. In the settings window, select the Hardware tab. This tab lists virtual devices such as memory, processors, network adapters, and hard disks.

3. Start the New Hardware wizard

Choose Add to begin the hardware-addition workflow. Select Hard Disk as the hardware type, then continue through the wizard until VMware displays the disk setup choices.

4. Choose a compatible disk interface

When VMware asks for the virtual disk type or controller interface, select an interface supported by the target VM and guest OS. The exact choices depend on the VMware version, the VM hardware version, and the guest.

For a secondary data disk, a compatible existing controller or the wizard's default is usually the safest choice. A controller choice that the guest lacks drivers for can cause the disk not to appear after startup.

5. Select Use an existing virtual disk

Choose the option to use an existing virtual disk, not the option to create a new virtual disk. Browse to the disk location and select the appropriate VMDK descriptor file.

Some virtual disks are split across several extent files. Others use a snapshot chain in which a newer child disk depends on one or more parent disks. Select the top-level descriptor intended for the disk and keep every related file in its expected location. Do not select an individual extent file when a descriptor file is available.

Finish the wizard. Return to the Hardware tab and verify that the new hard disk appears in the VM's hardware list. Save or accept the settings before starting the VM.

Select VM in Library > Player > Manage > Virtual Machine Settings > Hardware > Add > Hard Disk > choose disk interface > Use an existing virtual disk > browse to disk file > Finish

Workflow summary

Step — VMware Workstation Player action — Expected result

Select VM — Choose the target VM in the library — The correct VM is ready for configuration.

Open settings — Open the management menu and virtual machine settings — The hardware configuration is displayed.

Add disk — Use Add and select Hard Disk — The New Hardware wizard starts.

Select existing disk — Choose the existing-disk option and browse to the disk — The disk file is attached to the VM hardware.

Verify in guest — Start the VM and inspect guest storage — The volume is mounted or ready for guest-side configuration.

Start the guest and verify the disk

Power on the VM after confirming the hardware change. A guest OS that supports the disk's partitioning scheme and filesystem may detect and mount the volume automatically.

Detection does not guarantee that the volume will receive a Windows drive letter, a Linux mount point, or immediate visibility in the file browser. Use the guest OS disk-management tools to verify the physical disk, its partitions, and its filesystem before opening files.

  • On Windows, inspect the disk in Disk Management. An existing volume may need to be brought online or assigned a drive letter.
  • On Linux, inspect block devices and filesystems with the distribution's storage tools. A detected partition may need to be mounted at a directory.
  • On another guest OS, use its equivalent disk-management interface to rescan storage, identify the partition, and mount it according to that system's rules.

Guest operating system handling

The guest must support the disk's partition table and filesystem. For example, attaching a disk successfully in VMware does not make an unsupported filesystem readable by the guest.

If the disk is detected but is not shown in the file manager, the appropriate follow-up may be to bring it online, assign a drive letter, mount an existing partition, or import and activate storage according to the guest OS. These actions should expose an existing volume; they should not create a new one.

Disk files, chains, and compatibility

Workstation Player expects a compatible VMware virtual disk format and valid disk metadata. A disk may consist of more than one file, so copying or moving only one file can make the disk incomplete.

  • Split virtual disk: Several related extent files store one virtual disk. Keep all of them together.
  • Snapshot chain: A later disk state depends on parent disk files. Selecting a snapshot child without its parents can make the disk unusable.
  • Locked disk: Another VMware process or running VM may still have the disk open.
  • Encrypted or damaged disk: Encryption, corruption, or incomplete transfers can prevent attachment.
  • Foreign format: A disk created by another virtualization platform may require conversion before reliable use in Workstation Player.

Preserve the complete disk directory and its relationships before moving or renaming files. If repair or conversion is necessary, make a backup first.

Secondary data disk versus boot disk

The steps above attach a disk as extra storage. Adding it does not automatically change the VM's boot order and does not make the VM start from that disk.

Booting an operating system from a transplanted disk is a separate task. It may require matching firmware mode, such as BIOS or UEFI, compatible virtual hardware, suitable controller drivers, and correct boot settings. A disk that works perfectly as a secondary data disk may still fail to boot.

Practical examples

Reuse a data disk in a test VM

Suppose a VMDK contains installers and test data. Power off the target test VM, open its settings, add a hard disk, choose the existing-disk option, and select the correct descriptor. After startup, verify that the guest recognizes the existing volume before using its files.

Recover files from a non-booting VM

Keep the failed VM powered off and preserve its original disk. Attach a copy of the relevant disk to a functioning helper VM as a secondary disk. Carefully identify the correct partitions, mount them without initializing or formatting, and copy the required files.

The disk is detected but absent from the file browser

If VMware lists the disk and the guest storage tool sees it, the volume may simply lack a drive letter or mount point. Bring it online where appropriate and mount the existing volume. Do not initialize it merely because the guest offers that option.

Troubleshooting

VMware cannot select or open the disk

Likely causes include selecting the wrong file, missing split-disk or parent-disk files, a lock held by another VM, corruption, encryption, an incomplete copy, or an unsupported format.

  • Confirm that all related files are present in their expected locations.
  • Select the primary VMDK descriptor rather than an individual extent when applicable.
  • Ensure no other VM or VMware process is using the disk.
  • Use a supported conversion or repair workflow only after preserving a backup copy.

The VM starts but the guest cannot see the disk

Power off the VM and confirm that the disk is listed in its Hardware configuration. Then check whether the selected controller is supported by the guest and has the required driver. After correcting the configuration, restart the guest or use its storage-management interface to rescan disks.

The disk is visible in disk management but contains no accessible files

The disk may be offline, lack a drive letter or mount point, use an unsupported filesystem, or belong to a storage arrangement that requires additional member disks. Mount the existing partition only when you understand its layout. Do not initialize or format the disk to make it appear accessible.

Attaching the disk could corrupt data

Data corruption is especially likely when the same writable disk is attached to multiple running VMs, when a snapshot chain was copied incompletely, or when recovery work modifies the only disk copy. Keep one writable user unless a supported shared-storage design is in place, preserve the complete chain, and work from a copy for recovery tasks.

Completion and cleanup

Attachment is complete when the disk appears in both the VMware Hardware tab and the guest OS storage-management tools, and the intended existing volume is mounted or otherwise accessible.

When the disk is no longer needed, return to the VM's Hardware settings, select the added hard disk, and choose the removal option. Read the prompt carefully. Choose the option that removes the disk from the VM without deleting the underlying virtual disk files when you want to preserve the disk for later use.

Deleting the virtual disk files is different from disconnecting the disk. Do not approve a deletion option unless you intentionally want to remove the data.

Exam-relevant notes

  • Attaching an existing disk adds storage to a VM; it does not create a blank disk.
  • The target VM should be powered off before hardware changes.
  • A VMDK may depend on related extent or parent files.
  • A successful VMware attachment does not guarantee guest-side mounting.
  • Never initialize or format an existing data disk when trying to recover its contents.
  • Adding a disk does not automatically change the VM boot disk or boot order.
  • Removing a disk from VM hardware does not have to delete its underlying files.

For this procedure, see the guide to adding an existing virtual hard disk.