Have you ever wondered what the anatomy of a virtual machine (VM) is? If so, this post will show you what files make up a VMware workstation virtual machine. It will cover the many extensions associated with a VMware virtual machine.


A virtual machine is simply a set of relative files that contain the computer’s pertinent information. These files can be moved from computer to computer and will open up and work fine. This is a great feature because if you have a computer catastrophe, a simple backup will give you the entire computer back again if you are working from within a virtual machine. The virtual machine is made up of the files in Table 1.

Table1. Anatomy of a virtual machine

VMware Extension Name of File Description
.flp Floppy If you attach a Floppy Image through the Add Hardware Wizard Under VM | Settings | Hardware | Add, a blank Floppy.flp image is created in this directory.
.vmx.lck Lock When you select a virtual machine from the Favorites tab or when you choose File | Open and browse to a virtual machine, the lock file is created. As soon as you close the VMware Workstation tab that represents the opened VM or exit VMware Workstation, the lock file disappears.
.log vmware.log This is a log file that tracks the activity of the virtual machine in question. It is very helpful when debugging and troubleshooting issues that might arise.
.nvram [VM Name] .nvram Just as a PC has a BIOS, every virtual machine must have a BIOS as well. The .nvram file is, simply stated, the file that stores the BIOS.
.vmem [VM- Name-Name of Snapshot] When you take a snapshot, a vmem or virtual memory file is created to store the memory of the snapshot.
.vmsd [VM Name].vmsd This file stores metadata and snapshot information on one centralized location.
.vmx [VM Name].vmx The .vmx file is the configuration file that stores all the settings that are selected when you create a new virtual machine via the wizard. You can open the .vmx file with Notepad to view its contents. Inside you will see such things as the guest OS you are running. Once you get the hang of creating virtual machines, you can modify the settings in the .vmx file to more advanced configurations such as clustering and starting VMware Workstation as a service.
vmdk [VM Name].vmdk The .vmdk is the actual hard drive of your virtual machine. All the data is stored in this file. During the wizard, you can either configure a set amount of space for your virtual hard drive or have it auto-grow; it is your choice. Additionally, you can have the data split in 2GB chunks as well, which helps out if you ever have to zip or back up the virtual files to media.
.vmdk [VM Name]-xxxxx.vmdk When you have snapshots, a redo log file is created. The redo log file stores changes to the virtual disk while the virtual machine is in a running state. Furthermore, if you are splitting your disks into 2GB files, the naming convention becomes more complex.
.vmsn [VM Name] – Snapshot.vmsn This file is the VMware Workstation virtual machine snapshot. This file stores the running state of your virtual machine at the point-in-time that you take the snapshot.
.vmss [VM Name].vmss When you click the suspend toolbar button to suspend a virtual machine, the information about VMware Workstation virtual machine’s suspended state is stored in this file.
.vmxf [VM Name].vmxf When you create a virtual machine team and add a virtual machine to the team, the .vmxf team configuration file is added to the virtual machine directory.