Fix “Could not open /dev/vmmon” Error on Linux

Fix “Could not open /dev/vmmon” Error on Linux | VMware Workstation...

After the configuration of the operating system for installation on VMware Workstation, when you click on Start up this guest operating system, you have to face another error- Could not open /dev/vmmon: No such file or directory. Please make sure that the kernel module 'vmmon' is loaded.

To fix this error, we have to install and configure vmmon, vmnet, and dependencies. For the process, you can close the VMware Workstation.

Open the terminal and process the following command.
```
sudo vmware-modconfig --console --install-all
```
Update the system-
```
sudo apt update
```

Install build-essential linux-headers-

sudo apt install build-essential linux-headers-$(uname -r)

Configure and install VMware modconfig console-

sudo vmware-modconfig --console --install-al

Check if secure boot is enabled or not. If not, you can enable it from the system BIOS.
```
mokutil --sb-state
```
Configure the vmmon-
```
lsmod | grep vmmon
```
```
sudo modprobe vmmon
```
Install mokutil and openssl-
```
sudo apt install mokutil openssl
```
Create a directory for VMware signing-
```
mkdir -p ~/vmware-signing
```
Open the directory-
```
cd ~/vmware-signing
```

Download and configure the VMware Module Signing Key-

openssl req -new -x509 -newkey rsa:2048 -keyout MOK.priv -outform DER -out MOK.der -nodes -days 36500 -subj "/CN=VMware Module Signing/"

Import the MOK-
```
sudo mokutil --import MOK.der
```
Here, set a minimum of 4 digits of password, and confirm the same password again
Restart your system-
```
reboot
```
While rebooting the system, here press any key within 10 seconds to perform MOK management-

Here, select Enroll MOK and press enter-

Here, select Continue and press Enter-

Here, select Yes and press enter-

Now, type the password that we have set on the terminal and press enter-

Here, select Reboot and press Enter-
After a successful start, your system processes the next command in the Terminal.

Configure the vmmon, and vmnet
```
modinfo -n vmmon
```
You will latest module version info of the vmmon, which will be used in the upcoming command
```
modinfo -n vmnet
```
You will latest module version info of the vmnet, which will be used in the upcoming command

Import the latest module of vmmon and vmnet, make sure to change to the recent version of vmmon or vmnet.

sudo /usr/src/linux-headers-$(uname -r)/scripts/sign-file sha256 ~/vmware-signing/MOK.priv ~/vmware-signing/MOK.der /lib/modules/6.17.0-19-generic/misc/vmmon.ko

sudo /usr/src/linux-headers-$(uname -r)/scripts/sign-file sha256 ~/vmware-signing/MOK.priv ~/vmware-signing/MOK.der /lib/modules/6.17.0-19-generic/misc/vmnet.ko

Linux to unload (remove) the VMware kernel modules vmmon and vmnet from the running kernel.
```
sudo modprobe -r vmmon vmnet
```
Loads the vmmon and vmnet kernel modules into the running Linux kernel.
```
sudo modprobe vmmon
```
```
sudo modprobe vmnet
```
Check if vmmon and vmnet are loaded or not.
```
lsmod | grep vmmon
```
```
lsmod | grep vmnet
```