How to fix VMware Workstation VMCIDevVMX error on Windows

VMware Workstation is really useful for running virtual machines, but having errors in it is never a pleasant experience. Especially if you've invested a lot in the operating system you've created.

Although the problem looks complicated, this VMware Workstation error is actually very easy to fix.

If you get the "Unable to Open Kernel Device 'VMCIDev/VMX'" error on your Windows device when trying to run the virtual machine, this article will show you how to fix the problem in minutes.

How to fix the error "VMware Workstation Error: Unable to Open Kernel Device 'VMCIDev/VMX'"

So what is causing this error? Thankfully, the error message itself gives us enough information to determine the cause.

The "VMCI" error stands for "Virtual Machine Communication Interface". It provides efficient and fast communication between a virtual machine and the host operating system, and between two or more virtual machines on the same host. VMCI is present in all virtual machine vendors such as VMWare, VirtualBox, and Hyper-V.

As such, to fix the problem, we have to solve the VMCI. So let's get on with fixing this.

1. Fix VCMI

To resolve this error, you need to edit the VMX file of the virtual machine where the error occurs. The VMX file contains settings for the virtual machine's hard drive, memory, and processor limits.

Step 1: Locate the virtual machine folder.

Step 2: Search for the VMX file. It doesn't have to end with the VMX suffix. Look for an icon that looks like three blank pages.

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Step 3: Open the file with Notepad or any text editor.

Step 4: Search for the line with vmci0.present.

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Step 5: Change the value from "TRUE" to "FALSE".

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Step 6: Save and close the file.

Step 7: Restart your computer.

Now your virtual machine should run without any problems.

2. Uninstall and reinstall VMware Workstation

If the first fix doesn't work, uninstall the VMware Workstation program and reinstall it. This will reset it and you can then use your virtual machines again. Here are how to uninstall programs on Windows 10 and some other ways to uninstall software in Windows 11.

Now, you know how to fix this VMWare error. Hopefully the above steps have completely resolved your issue and your VMs are now up and running. However, if the error persists, you can try contacting the VMWare support team.