What does "vmware cannot open configuration file vmx" mean?

The error “vmware cannot open configuration file vmx” means VMware cannot access the virtual machine’s .vmx file, which stores its hardware and runtime settings. This usually happens when the file is missing, corrupted, locked by another process, or blocked by datastore permission issues. Without the .vmx file, VMware cannot power on the VM because it doesn’t know how to configure its virtual hardware. Common triggers include stale lock files, abrupt host crashes, NFS permission misconfigurations, or accidental deletion of the .vmx. In short, the error signals that VMware has lost access to the VM’s core configuration file and needs repair or recovery before the VM can run again.

Can I fix the "cannot open configuration file vmx" error without losing data?

Yes — in most cases. Lock file removal, stale .vmx~ deletion, NFS permission correction, and VMX file rebuilding from an intact VMDK all preserve data completely. Data loss risk only arises if the VMDK flat file itself is damaged or deleted, which is a separate issue from the VMX error.

What does "vmx configuration file not found" mean on ESXi?

On ESXi, the “vmx configuration file not found” error means the hypervisor cannot locate the .vmx file that defines a virtual machine’s hardware and runtime settings. This usually happens if the file was accidentally deleted, the datastore was renamed or remounted under a new UUID, or the VM was moved outside of vCenter’s migration tools. Without the .vmx file, ESXi has no blueprint to power on the VM, even if the virtual disks (.vmdk) are still present. In some cases, the file exists on the datastore but vCenter has lost its reference, requiring re‑registration. In short, the error signals that ESXi cannot find the VM’s configuration file and you must either re‑register, rebuild, or restore it before the VM can run again.

How do I find which process is locking my VMX file on ESXi?

On ESXi, you can identify which process is locking a .vmx file by using VMware’s built‑in lock inspection tools (vmfsfilelockinfo and esxcli vm process list). These commands reveal the process or VM Cartel ID holding the lock so you can decide whether to stop, migrate, or reboot the host to release it.

Is it safe to delete the .vmx.lck folder in VMware Workstation?

Yes, it is safe to delete the .vmx.lck folder in VMware Workstation if the VM is powered off and Workstation is fully closed. These lock folders are temporary and are created to prevent concurrent access to the VM’s configuration file while it is running. If Workstation crashes or is force‑terminated, the lock folder can remain orphaned and block the next startup. Removing the .vmx.lck folder simply clears the stale lock, and VMware will recreate it automatically when the VM is powered on again. Just make sure no VMware processes are running before deletion to avoid interfering with an active session.

What happens if I delete the .vmx~ file on an ESXi host?

On an ESXi host, the .vmx~ file is just a temporary working copy of the VM’s configuration created when the VM powers on. Normally, ESXi deletes it when the VM shuts down cleanly. If you delete a .vmx~ file while the VM is running, you risk corrupting the session or causing the VM to crash because the hypervisor is actively using it. If the VM is powered off and the .vmx~ file is stale (left behind after a crash or failed operation), it is safe to remove or rename it to clear the lock. In short, only delete a .vmx~ file when the VM is confirmed powered off — never during active operation.

Can DiskInternals VMFS Recovery™ recover a deleted VMX file?

Yes — DiskInternals VMFS Recovery™ can recover a deleted .vmx file from a VMFS datastore.\nIt is designed to read VMware’s proprietary VMFS filesystem, locate deleted or corrupted VMX and VMDK files, and restore them even when ESXi cannot mount the datastore.

VMware Cannot Open Configuration File VMX: All Causes, All Fixes, and How to Recover When Data Is at Risk

When VMware Workstation or ESXi throws the error “Cannot open configuration file .vmx”, it usually signals a critical problem with the virtual machine’s metadata. The .vmx file is the core configuration file that defines a VM’s hardware settings, disk mappings, and runtime parameters — without it, VMware cannot boot the guest. This issue can arise from corrupted files, failed migrations, accidental deletions, or storage layer problems. For IT administrators and developers, the error can mean downtime, lost productivity, or even potential data loss if not addressed quickly. In this guide, we’ll break down the common causes of .vmx errors, practical fixes you can apply, and recovery strategies to restore your VM environment safely.

Understanding the Error: What "Cannot Open Configuration File VMX" Actually Means

What the Error Message Looks Like

The “VMware cannot open configuration file VMX” error typically appears in the vSphere Client task pane, the ESXi host’s vmware.log, or VMware Workstation’s error dialog. On ESXi, the full message looks like:

<code class="language-text">Cannot open the configuration file /vmfs/volumes/[datastore]/[VM directory]/[VMname].vmx</code>

It is often followed by a reason code that identifies the underlying issue:

16 — Device or resource busy
13 — Permission denied
Could not find the file — Missing from datastore
The file already exists — Stale .vmx~ temporary file present
Failed to get exclusive lock — Another process or host is holding the file lock``````````

Why VMware Locks the VMX File at Power‑On

When ESXi powers on a VM, it acquires an exclusive Mode 1 lock on the .vmx configuration file and creates a temporary working copy named VMname.vmx~. This lock ensures that only one ESXi host can run the VM at a time and protects configuration integrity during updates. Normally, the lock is released at power‑off and the .vmx~ file is deleted. If the lock persists — due to a host crash, abrupt disconnection, failed vMotion, or interrupted backup — the next power‑on attempt encounters a conflict, triggering the “Cannot open configuration file” error.

Note: What is a VMX file?

📊 Error Code Reference Table: Cannot Open Configuration File VMX

Error Code / Reason	Meaning	Primary Cause
16 (Device or resource busy)	VMX file locked by an active or stale process	VM already running on another host; stale ESXi process; interrupted vMotion
13 (Permission denied)	Host lacks read/write access to the VMX file	NFS datastore permission misconfiguration; No Root Squash disabled
Could not find the file	VMX file absent from the datastore path	File deleted, moved, or path reference broken after datastore rename
The file already exists (errno 17)	Stale .vmx~ temporary file blocking creation	ESXi crashed mid-operation, leaving temporary file on datastore
Failed to get exclusive lock	Lock file (.vmx.lck) held by orphaned process	VMware Workstation crashed; second instance running same VMX

Cause 1: Stale .vmx~ Temporary File — ESXi Fix

Why the .vmx~ File Gets Left Behind

When ESXi powers on a VM, it creates a temporary working copy of the configuration file named .vmx~. This file is normally deleted when the VM powers off. If the host crashes, loses power, or encounters a storage fault mid‑operation, the cleanup never happens. On the next power‑on attempt, ESXi tries to create a new .vmx~ file but fails with errno: 17 (The file already exists), resulting in the “vmware cannot open configuration file vmx” error.

Step‑by‑Step Fix: Remove the Stale .vmx~ File (ESXi SSH)

This procedure follows VMware/Broadcom KB 308383:

1. Open SSH session to the ESXi host where the VM is registered.
2. Navigate to the VM’s directory on the datastore:

<code class="language-bash">cd /vmfs/volumes/[datastore]/[VM directory] ls -ltrah</code>

3. Confirm the presence of a file ending in ~ (e.g., VMname.vmx~).
4. Check for active locks on VM files:

<code class="language-bash">for file in *; do vmfsfilelockinfo -p "$file" | awk '{FS = "\n"; RS = ""} {print $2 , $7}'; done</code>

5. Verify VM registration and ID:

<code class="language-bash">vim-cmd vmsvc/getallvms</code>

6. Confirm VM is powered off:

<code class="language-bash">vim-cmd vmsvc/power.getstate [vmid]</code>

7. Rename the stale file to avoid blocking startup:

<code class="language-bash">mv VMname.vmx~ VMname.vmx_bak</code>

8. Power on the VM:

<code class="language-bash">vim-cmd vmsvc/power.on [vmid]</code>

9. Delete the backup file once the VM is running successfully. Keep it until the VM powers on, as it may serve as a fallback.

Tip: VMX to VHD

Cause 2: Stale Lock File (.vmx.lck) — VMware Workstation and ESXi Fix

How Lock Folders Work in VMware Workstation

VMware Workstation creates a lock folder named VMname.vmx.lck in the VM’s directory whenever the VM is running. This folder contains lock files that prevent concurrent access to the VM configuration. If Workstation crashes, is force‑terminated, or the storage device disconnects mid‑operation, the lock folder remains orphaned. On the next launch, Workstation encounters the stale lock and returns “Failed to get exclusive lock on the configuration file”, which is one form of the cannot open configuration file vmx error.

Step‑by‑Step Fix: Remove Orphaned .vmx.lck and .lck Folders (VMware Workstation)

1. Ensure VMware Workstation is fully closed. In Task Manager (Ctrl+Shift+Esc), end all vmware.exe and vmware-vmx.exe processes.
2. Navigate to the VM’s folder on disk (default: Documents\Virtual Machines\[VMname]\).
3. Locate and delete all .lck folders and files, such as:

VMname.vmx.lck\
VMname-flat.vmdk.lck\
VMname.vmsd.lck\

4. Optionally delete .vmss and .vmem files if present (these store suspended VM state). Removing them forces a cold boot from the last consistent disk state.
5. Relaunch VMware Workstation and power on the VM.

Note: Deleting .lck folders does not harm the VM. VMware recreates them automatically at next power‑on.

Step‑by‑Step Fix: Remove Stale Lock via ESXi SSH (vmfsfilelockinfo)

On ESXi, orphaned lock files require identifying the locking process before removal:

1. SSH into the ESXi host.
2. Navigate to the VM directory and run:

<code class="language-bash">ls | while read x; do vmfsfilelockinfo -p $x | grep -i "is locked"; done</code>

3. If a lock is detected, identify the holding process:

<code class="language-bash">lsof | egrep 'VMname.vmx'</code>

4. Cross‑reference the Cartel ID with active VM processes:

<code class="language-bash">esxcli vm process list</code>

5. If the lock belongs to a powered‑off VM (stale process), reboot the ESXi host to release it. For clusters, migrate live VMs off the host before rebooting.
6. If the lock is held by another active VM referencing the same VMDK (misconfiguration), power off the conflicting VM, correct the .vmx file, then restart the target VM.
7. As an alternative to rebooting, restart VMware management services:

<code class="language-bash">/etc/init.d/hostd restart /etc/init.d/vpxa restart</code>

Cause 3: Permission Denied on NFS Datastore

Why NFS Permissions Block VMX Access

The errno: 13 (Permission denied) error occurs when the ESXi host lacks proper read/write access to the NFS export hosting the datastore. The most common culprit is root_squash, which maps ESXi’s root UID (0) to an anonymous user. This prevents ESXi from acquiring the exclusive lock it needs on the .vmx file. For VMware environments, the NFS export must be configured with no_root_squash to allow ESXi to function correctly.

Fix: NFS Export Permissions

1. On the NFS server, verify export options for the datastore share. Ensure no_root_squash is set (not root_squash).
2. Confirm the ESXi host’s IP address is explicitly listed in the NFS export’s allowed host list with rw (read/write) permissions.
3. On the ESXi host, rescan the storage adapter after fixing NFS permissions:

Navigate to Storage → Adapters → Rescan All.

4. Attempt to power on the VM again. If the error persists, check whether the datastore is mounted read‑only (visible in datastore properties as Access: Read Only). If so, unmount and remount with read/write access.

Cause 4: VMX Configuration File Not Found — The File Is Missing

How the VMX File Goes Missing

The “vmx configuration file not found” error occurs when vCenter’s inventory points to a path that no longer contains a valid .vmx file. Common causes include accidental deletion via the Datastore Browser, datastore renaming or remounting under a new UUID, moving or copying the VM outside of vCenter’s migration tools, or a VMFS volume going offline and remounting with a different path.

Fix Option 1: Re‑Register the VM from the Datastore Browser

If the .vmx file still exists but vCenter lost its reference:

1. In the vSphere Client, go to Storage → Datastores → Datastore Browser.
2. Browse to the VM’s directory and confirm the .vmx file is present.
3. Right‑click the .vmx file and select Register VM.
4. Follow the wizard, then power on the VM to confirm operation.

Fix Option 2: Rebuild the VMX File Without Data Loss

If the .vmx file is truly absent but the VMDK remains intact:

1. In the Datastore Browser, create a new directory for the VM.
2. Upload the intact VMDK files into the directory.
3. Launch the New Virtual Machine Wizard, choose Use an existing virtual disk, and point to the VMDK descriptor file.
4. Match hardware settings to the original VM (OS type, vCPU, memory, NIC type).
5. Complete the wizard — ESXi generates a new .vmx file.
6. Register the VM by selecting the new .vmx file.
7. At the prompt “Did you move or copy this VM?”, select I Moved It to preserve UUID and MAC addresses. Choosing I Copied It generates new identifiers, which may break licensing or guest OS networking.

Fix Option 3: Restore the VM from Backup

If both the .vmx and VMDK files are missing or corrupted, restore the VM from the most recent backup. In ESXi environments without native backup, image‑level backups from third‑party tools provide the fastest recovery path. Without a backup, proceed to VMFS‑level recovery tools to attempt reconstruction.

Note: VMX configuration file

When Fixes Fail: Recovering VMX and VMDK Data from a Damaged VMFS Datastore

What to Do When the Datastore Itself Is the Problem

All four causes above assume the VMFS datastore is accessible. If the datastore itself is offline — due to controller failure, LUN reassignment, VMFS metadata corruption, or ESXi host failure — the .vmx file cannot be opened because the filesystem containing it cannot be mounted. In these cases, standard ESXi troubleshooting commands return no output. The data still resides on the physical storage but is unreachable through normal VMware paths.

Why Standard Recovery Tools Cannot Read VMFS

VMFS is VMware’s proprietary clustered filesystem. Tools designed for NTFS, ext4, APFS, or FAT32 cannot parse VMFS structures, interpret VMDK descriptor files, or reconstruct snapshot delta chains. Recovering .vmx and .vmdk files from a damaged or offline VMFS datastore requires a tool that natively understands VMFS.

DiskInternals VMFS Recovery™: VMX and VMDK Recovery from Inaccessible Datastores

DiskInternals VMFS Recovery™ is purpose‑built for VMware environments. It can:

Mount VMDK files directly without a running ESXi host — critical when the hypervisor is unavailable.
Recover deleted .vmx configuration files from VMFS volumes.
Reconstruct VMFS volumes with corrupted or partially overwritten metadata.
Connect directly to ESXi servers via IP and credentials for remote datastore scanning.
Provide file preview before extraction to confirm integrity.

Recommended workflow:

1. Connect DiskInternals VMFS Recovery™ to the affected VMFS volume or ESXi host.
2. Run a full scan to detect recoverable files.
3. Locate .vmx and .vmdk files in the recovery browser.
4. Preview file integrity before extraction.
5. Extract recovered files to a safe destination.
6. Re‑register the VM using the rebuilt .vmx file (see Fix Option 2 above).

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Prevention: Stopping "Cannot Open Configuration File VMX" Before It Happens

Use vSphere HA and Proper Power‑Off Procedures

Most cannot open configuration file vmx errors stem from abrupt host failures — power cuts, kernel panics, or forced VM terminations — that leave lock files and temporary VMX copies behind. Configure vSphere HA on production clusters so VMs restart automatically after host failures. Always shut down VMs via the vSphere Client’s “Shut Down Guest OS” option instead of cutting power directly.

Maintain Regular VMX File Backups

VMX files are plain text, only a few kilobytes in size, yet they contain the complete hardware blueprint for a VM. Back them up daily. A simple script can compress and archive every VMX file across datastores in seconds. The cost is negligible, but the recovery value when a VMX file is deleted or corrupted is immediate.

Monitor NFS Datastores for Permission Drift

NFS export permissions can change after OS updates, firmware upgrades, or infrastructure modifications. Add NFS mount permission verification to quarterly audits. Always confirm no_root_squash is set on VMware NFS exports after storage maintenance to prevent permission‑denied errors.

Clean Up Snapshots to Prevent Lock Chain Complexity

Snapshot chains that grow beyond three levels increase the risk of lock conflicts during power‑on and backup operations. Consolidate snapshots regularly. ESXi 7.x and 8.x raise alerts for VMs with snapshot chains exceeding 100 GB — act on these alerts promptly to avoid lock failures.

Tip: Fix VMware cannot open configuration file VMX

FAQ

What does "vmware cannot open configuration file vmx" mean?
The error “vmware cannot open configuration file vmx” means VMware cannot access the virtual machine’s .vmx file, which stores its hardware and runtime settings. This usually happens when the file is missing, corrupted, locked by another process, or blocked by datastore permission issues. Without the .vmx file, VMware cannot power on the VM because it doesn’t know how to configure its virtual hardware. Common triggers include stale lock files, abrupt host crashes, NFS permission misconfigurations, or accidental deletion of the .vmx. In short, the error signals that VMware has lost access to the VM’s core configuration file and needs repair or recovery before the VM can run again.
Can I fix the "cannot open configuration file vmx" error without losing data?
Yes — in most cases. Lock file removal, stale .vmx~ deletion, NFS permission correction, and VMX file rebuilding from an intact VMDK all preserve data completely. Data loss risk only arises if the VMDK flat file itself is damaged or deleted, which is a separate issue from the VMX error.
What does "vmx configuration file not found" mean on ESXi?
On ESXi, the “vmx configuration file not found” error means the hypervisor cannot locate the .vmx file that defines a virtual machine’s hardware and runtime settings. This usually happens if the file was accidentally deleted, the datastore was renamed or remounted under a new UUID, or the VM was moved outside of vCenter’s migration tools. Without the .vmx file, ESXi has no blueprint to power on the VM, even if the virtual disks (.vmdk) are still present. In some cases, the file exists on the datastore but vCenter has lost its reference, requiring re‑registration. In short, the error signals that ESXi cannot find the VM’s configuration file and you must either re‑register, rebuild, or restore it before the VM can run again.
How do I find which process is locking my VMX file on ESXi?
On ESXi, you can identify which process is locking a .vmx file by using VMware’s built‑in lock inspection tools (vmfsfilelockinfo and esxcli vm process list). These commands reveal the process or VM Cartel ID holding the lock so you can decide whether to stop, migrate, or reboot the host to release it.
Is it safe to delete the .vmx.lck folder in VMware Workstation?
Yes, it is safe to delete the .vmx.lck folder in VMware Workstation if the VM is powered off and Workstation is fully closed. These lock folders are temporary and are created to prevent concurrent access to the VM’s configuration file while it is running. If Workstation crashes or is force‑terminated, the lock folder can remain orphaned and block the next startup. Removing the .vmx.lck folder simply clears the stale lock, and VMware will recreate it automatically when the VM is powered on again. Just make sure no VMware processes are running before deletion to avoid interfering with an active session.
What happens if I delete the .vmx~ file on an ESXi host?
On an ESXi host, the .vmx~ file is just a temporary working copy of the VM’s configuration created when the VM powers on. Normally, ESXi deletes it when the VM shuts down cleanly. If you delete a .vmx~ file while the VM is running, you risk corrupting the session or causing the VM to crash because the hypervisor is actively using it. If the VM is powered off and the .vmx~ file is stale (left behind after a crash or failed operation), it is safe to remove or rename it to clear the lock. In short, only delete a .vmx~ file when the VM is confirmed powered off — never during active operation.
Can DiskInternals VMFS Recovery™ recover a deleted VMX file?
Yes — DiskInternals VMFS Recovery™ can recover a deleted .vmx file from a VMFS datastore.
It is designed to read VMware’s proprietary VMFS filesystem, locate deleted or corrupted VMX and VMDK files, and restore them even when ESXi cannot mount the datastore.

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