VMware Workstation Player course

VMware Workstation Player Virtual Machine Files: Purpose and File Types

Learn what VMware Workstation Player VM files mean, including VMX, VMDK, NVRAM, VMEM, logs, VMSS, VMSD, and VMSN files, plus safe backup and maintenance practices.

A VMware virtual machine (VM) is a software-defined computer. Its settings, virtual disks, firmware state, and runtime information are stored as files on the host operating system—the physical computer that runs VMware Workstation Player. The operating system installed inside the VM is the guest operating system.

Instead of being represented by one file, a VM normally appears as a folder on the host. The folder contains a primary configuration file, one or more virtual disks, and optional firmware, memory, suspend, snapshot, and diagnostic files.

VM folder overview

The VM folder is the unit you should normally preserve when backing up or moving a virtual machine. Its exact contents change according to the VM's activity and configuration. A powered-off VM may contain only its configuration, firmware, disk, and log files. Running or suspended VMs can create memory and state files, while snapshot-enabled installations can contain additional snapshot files.

  • Configuration: Describes the virtual hardware and VM options.
  • Virtual disk: Stores the guest operating system, applications, files, and filesystem data.
  • Firmware: Preserves the VM's virtual BIOS or UEFI settings.
  • Runtime state: Supports suspended or otherwise preserved in-progress sessions.
  • Snapshot data: Records snapshot relationships, metadata, and saved state when snapshots are used.
  • Diagnostics: Records startup activity, device initialization, warnings, and errors.

The folder's name and the files' base names often reflect the VM name, but extensions are more useful than names for identifying roles.

VMware virtual machine file reference

File type | Typical filename or extension | Primary purpose | When it appears | Safe handling guidance .vmx configuration file | Ubuntu 16.vmx | Main VM definition: memory, processors, disks, network adapters, and other virtual hardware | Normally present for every VM | Safe to inspect when powered off; back up before editing and prefer the VMware interface for changes .nvram firmware file | Ubuntu 16.nvram | Stores virtual BIOS or UEFI settings | Usually created when firmware state is initialized | Do not delete or replace casually; doing so can reset firmware-level settings .vmdk virtual disk file | Ubuntu 16.vmdk and related files | Stores the guest's virtual hard-disk data | Present for each configured virtual disk | Never delete, rename, or move one disk component independently .log diagnostic file | vmware.log or VM-name-based .log | Records startup events, device activity, warnings, and errors | Generated or updated during VM runs | Usually safe to read; logs are not guest disk data .vmem memory or paging file | Ubuntu 16.vmem | Host-side storage associated with VM memory or paging | Depends on configuration and runtime state | Do not edit or remove while the VM is in use .vmsd snapshot metadata file | Ubuntu 16.vmsd | Stores snapshot inventory and metadata | When snapshot information exists | Handle with the related snapshot files; do not delete manually to reclaim space .vmsn snapshot state file | Ubuntu 16-Snapshot1.vmsn | Stores saved VM state associated with a snapshot, where applicable | When a snapshot includes saved state | Keep with its snapshot and disk relationships .vmss suspended-state file | Ubuntu 16.vmss | Records the state of a suspended VM | When the VM is suspended | Resume and shut down normally before moving, copying, or maintaining the VM

The .vmx configuration file

The .vmx file is the main virtual machine definition. It is a text-based file containing descriptions of the VM's virtual hardware and options. Its settings can include allocated memory, processor count, virtual disk references, virtual network adapters, CD/DVD devices, USB behavior, and compatibility information.

You can inspect a VMX file with a plain text editor, but first power off the VM. Do not inspect or modify it while VMware is actively using the VM. Create a backup copy before making any change. A typo, unsupported value, or broken disk reference can prevent startup or change the VM's behavior.

For normal changes, use VMware Workstation Player's settings interface. The VMX file is not a general-purpose configuration document: edit it manually only when you understand the specific setting and its consequences.

The .nvram virtual firmware file

NVRAM means nonvolatile random-access memory. In a VM, the .nvram file preserves virtual BIOS or UEFI firmware settings, such as firmware-level choices made for that guest.

This is separate from the physical host computer's BIOS or UEFI. Changing the host's firmware is not the same as changing the firmware settings presented to a guest VM. Deleting or replacing the NVRAM file can reset virtual firmware configuration, so do this only deliberately and with a recovery plan.

The .vmdk virtual disk files

A .vmdk file uses VMware's virtual disk format. It represents a virtual hard disk presented to the guest operating system. The guest's operating system, installed applications, user documents, and filesystem contents reside in the virtual disk rather than in the VMX file.

One VM can have several virtual disks. Also, one virtual disk can be represented by more than one related VMDK file, depending on its format, size, split-file arrangement, and snapshot usage. A small descriptor file may refer to larger extent files, and snapshot chains may add related disk components.

Attaching an existing VMDK to another VM is a separate storage-management task from copying a complete VM. For that task, see Adding An Existing Virtual Hard Disk. For an overview of virtual disk behavior, see Virtual Disks Explained.

The .vmem memory and paging file

The .vmem file is host-side storage associated with the VM's memory or paging requirements. Its presence and size depend on the VM's configuration and runtime state. It is not an ordinary document created by the guest operating system.

Do not edit or remove a VMEM file while the VM is running, suspended, or otherwise in use. A large VMEM file is not automatically safe to delete; use normal VMware power-state and storage-management workflows instead.

VMware .log files

Files such as vmware.log and VM-name-based log files are diagnostic records. They can contain startup events, virtual hardware initialization, virtual device activity, warnings, and errors.

Logs are useful when investigating startup failures and virtual disk, graphics, networking, or device problems. They are not the guest's disk data, and VMware typically creates or updates logs during later VM runs. It is normally safe to read a log with a text editor, preferably after powering off the VM or making a copy for analysis.

Snapshot metadata and state files

A snapshot is a point-in-time preservation mechanism involving metadata, saved state, and relationships between virtual disks. It is not a standalone replacement for a backup.

  • .vmsd: Stores snapshot inventory or metadata, such as the snapshot structure.
  • .vmsn: Stores saved VM state associated with a snapshot, including running-state information when applicable.

Snapshot metadata and state are different from the guest's ordinary virtual disk contents. Snapshot operations can also create or depend on related VMDK files.

Snapshot creation and management are associated with VMware Workstation Pro and may not be available for creation or management in Workstation Player. Do not manually remove VMSD, VMSN, or related disk files to reclaim space. They must be handled as a set through supported VMware workflows.

Suspended VM state: the .vmss file

The .vmss file records the state of a suspended VM. Suspending pauses an in-progress guest session while preserving enough state to resume it later. Shutting down is different: the guest operating system closes normally and the VM reaches a powered-off state.

A suspended VM depends on matching state files, configuration, and virtual disk files. If the VMSS file or its related files are moved, deleted, or changed, the VM may not resume correctly.

Before copying, relocating, or performing maintenance, resume the VM and shut it down normally. If you cannot resume it, preserve a copy of the entire VM folder before using VMware's normal recovery or discard-suspended-state workflow.

VM power state and expected file behavior

VM condition | Relevant files | Management recommendation Powered off | .vmx, .vmdk, .nvram, and existing logs; optional state files may remain | Best state for backup, migration, inspection, and manual file work Running | Configuration and disk files are actively used; logs may update and memory-related files may exist | Do not move, rename, or edit VM files; shut down normally before maintenance Suspended | .vmss and possibly .vmem, plus matching configuration and disk files | Resume and shut down before copying or relocating; preserve the complete folder Snapshot-related state | .vmsd, .vmsn, and related VMDK files where snapshots exist | Manage through supported VMware tools; never remove individual files manually

How to locate and manage the VM folder safely

Locate the folder

  1. Open VMware Workstation Player and identify the VM in the library or home screen.
  2. Open the VM's configured storage location using the VMware interface, or inspect the location shown in the VM's details and settings.
  3. Use the host operating system's file manager to open that directory.
  4. Confirm that the folder contains the expected VMX and VMDK files before moving or copying anything.

The exact default location varies by host operating system and by the storage location selected when the VM was created. Do not assume that every VM is stored in one default directory.

Inspect versus edit

  • Normally suitable for inspection: .vmx files, when the VM is powered off, and .log files.
  • Not suitable for text editing: .vmdk, .nvram, .vmem, .vmss, .vmsd, and .vmsn files.
  • Do not treat a readable file as a disposable file: binary or state files may be essential even when their purpose is not obvious.

Back up a complete VM

  1. Shut down the guest operating system normally. Do not leave the VM running or suspended.
  2. Wait until VMware shows the VM as powered off.
  3. Copy the entire VM folder, including the VMX, all VMDK components, NVRAM, logs, and any state or snapshot files that belong to the VM.
  4. Keep the folder structure and file relationships unchanged in the backup.
  5. Verify the copied VM on the target host before relying on it as a backup.

Moving or renaming a VM should be done through VMware tooling when possible. If you use the host file manager, preserve the complete folder and all associated filenames and relationships. Moving only the visible VMDK or only the VMX file is not a complete VM migration.

Example: interpreting an Ubuntu VM folder

The following is a representative listing for a VM named Ubuntu 16:

Ubuntu 16.vmx
Ubuntu 16.nvram
Ubuntu 16.vmdk
vmware.log
Ubuntu 16.vmem
Ubuntu 16.vmss
Ubuntu 16.vmsd
Ubuntu 16.vmsn
  • Ubuntu 16.vmx: Defines the virtual hardware and VM settings.
  • Ubuntu 16.nvram: Stores the guest's virtual BIOS or UEFI state.
  • Ubuntu 16.vmdk: Stores the Ubuntu guest's virtual hard-disk data. It may have additional related files in a real VM folder.
  • vmware.log: Records VMware diagnostic information for recent VM activity.
  • Ubuntu 16.vmem: Holds host-side memory or paging-related data when required.
  • Ubuntu 16.vmss: Preserves a suspended session if the VM was suspended.
  • Ubuntu 16.vmsd: Stores snapshot inventory and metadata when snapshot information exists.
  • Ubuntu 16.vmsn: Stores saved state associated with a snapshot when applicable.

The example includes optional files for illustration. VMEM, VMSS, VMSD, and VMSN may be absent if the VM has never been suspended, snapped, or run in a state that creates them. A folder can also contain multiple logs or several VMDK-related files.

Related storage-management tasks

Attaching an existing VMDK to another VM lets you reuse a virtual disk without treating it as a complete VM. This requires care because the disk may contain an operating system, applications, or data that another VM could modify.

Virtual disk compaction is a storage-reclamation operation intended to reduce unused physical host storage consumed by a virtual disk. It should be performed only under appropriate conditions, after a backup, and through supported VMware procedures. See Compacting A Virtual Hard Disk.

Troubleshooting common file problems

The VM no longer starts after its folder was moved

  • A related VMDK component or another dependent file may not have been moved.
  • A VMX reference may no longer point to the expected disk location.
  • The VM may have been copied while running or suspended.

Restore the complete VM folder from a known-good copy if possible. Confirm that the expected configuration and disk files are present, then review the latest VMware log for missing-file or configuration errors. Do not create replacement files with matching names until the original relationships are understood.

The VM cannot resume after suspension

The VMSS file or associated files may have been moved, deleted, or changed, or the host may have interrupted access to the folder. Preserve a copy of the VM folder first. Then use VMware's normal resume or discard-suspended-state workflow only when appropriate. If recovery is not possible, return to a powered-off state and validate the VMDK and VMX files.

Large files appear to be consuming host storage

VMDK, VMEM, VMSS, and snapshot-related files can be large. Do not delete them merely because of their size. Shut down the VM, make a backup, and use supported VM and disk-management workflows, including compaction where applicable.

A manual VMX edit causes unexpected behavior

An invalid setting, typo, incompatible value, or broken disk reference may have been introduced. Revert to the backed-up VMX file, use VMware's graphical settings interface for normal changes, and inspect the log to identify the setting VMware could not process.

Exam-relevant summary

  • A VM is represented by a host folder, not a single file.
  • .vmx is the primary text-based VM configuration file.
  • .vmdk contains the guest's virtual disk data and may consist of related files.
  • .nvram stores virtual BIOS or UEFI state, not the host's physical firmware settings.
  • .vmem is host-side memory or paging-related storage.
  • .log files are diagnostic records, not guest disk data.
  • .vmss stores suspended VM state.
  • .vmsd stores snapshot metadata, while .vmsn stores snapshot state.
  • Power off the VM before backup, migration, inspection, or manual file work.
  • A complete backup copies the entire VM folder and preserves all file relationships.

For broader context, see Virtual Machine Explained and the VMware Workstation Player Course.