What Is the VMX File in VMware and How Is It Used?

A typical VM folder contains VMDK files (the virtual disks), log files and the VMX file. The VMDK holds the data, and the VMX file defines settings like the number of virtual CPUs, allocated memory, network adapters, virtual hardware version, disk attachments and boot options.

For advanced configuration changes, administrators can download the VMX file and edit it in a text editor. For example, parameters such as numvcpus and memsize can be changed while the VM is powered off. The new configuration takes effect once you save the changes and reboot the VM. Edit carefully, though, because a syntax error can stop the VM from powering on.

If a VM fails because its VMX file is corrupted, you can recreate it by removing the VM from inventory and registering a new VM with the existing virtual disk. The newly generated VMX file restores a working configuration.

In short, the VMX file is the blueprint of a virtual machine: it defines how the VM is built and how it runs.

Q1: Where is the VMX file located?

It is stored inside the VM's folder on the datastore.

Q2: Can the VMX file be edited manually?

Yes, but power off the VM and make a backup copy of the file first.

Q3: What happens if the VMX file is corrupted?

You can recreate the VM configuration and register the VM again using the existing virtual disk.

Q4: Does the VMX file store VM data?

No. It stores configuration settings, and the actual data lives in the VMDK files.