VMWARE 16: Can't Load Guest on Ubuntu 20.04 LTS - "Could not open /dev/vmmon" Error

I am having an issue with VMWare on Linux.After trying to launch an Ubuntu or Windows Guest on a host running Ubuntu 20.04 LTS 64-BIT, I am presented with the following three errors:

Could not open /dev/vmmon: No such file or directory. Please make sure that the kernel module ‘vmmon' is loaded.

After clicking OK, the 2nd error:

Failed to initialize monitor device.

After clicking OK on the 2nd error, the 3rd error:

Unable to change virtual machine power state: Transport (VMDB) error -14: Pipe connection has been broken

Host Info: AMD 64-Bit FX9800 8-core CPU, 32GB Ram, plenty HDD Space. OS: Ubuntu 20.04 LTS running latest kernel 5.11.0-40-generic. VMware Workstation Pro 16.2.1 (build 18811642). UEFI - Secure Boot Enabled. Single Boot Only - No Windows Partition.

Guest Info: Both Ubuntu and Windows guests are set to boot via BIOS and not UEFI. I tried creating a new VM using UEFI and the same issue occurred.

Steps I have so far taken:

• Uninstalled via terminal command sudo vmware-installer -u vmware-workstation, rebooting, then re-installing via sudo sh VMware-Workstation-Full-16.2.1-18811642.x86_64.bundle (installed via CLI - did not use GUI installer). I then rebooted, same issue. Both with previous VM and brand new VM.

• Physically at host machine, uninstalled via terminal command sudo vmware-installer -u vmware-workstation, rebooting, then re-installing via sudo sh VMware-Workstation-Full-16.2.1-18811642.x86_64.bundle. I then rebooted, same issue. Both with previous VM and brand new VM.

• Confirmed dkms is installed and all updates are installed. Installed packages linux-tools-generic-hwe-20.04, libelf-dev, linux-generic, fdutils, then uninstalled VMWare, rebooted and re-installed VMware. Same issue when launching guest VMs.

• Tried generating SSH keys as per https://kb.vmware.com/s/article/2146460:

  $ openssl req -new -x509 -newkey rsa:2048 -keyout MOK.priv -outform DER -out MOK.der -nodes -days 36500 -subj "/CN=VMware/"
  $ sudo /usr/src/linux-headers-`uname -r`/scripts/sign-file sha256 ./MOK.priv ./MOK.der $(modinfo -n vmmon)
  $ sudo /usr/src/linux-headers-`uname -r`/scripts/sign-file sha256 ./MOK.priv ./MOK.der $(modinfo -n vmnet)
  $ mokutil --import MOK.der
  

• Signed the modules using sudo /usr/src/kernels/$(uname -r)/scripts/sign-file sha256 ./MOK.priv ./MOK.der $(modinfo -n vmmon) and sudo /usr/src/kernels/$(uname -r)/scripts/sign-file sha256 ./MOK.priv ./MOK.der $(modinfo -n vmnet)

• Rebooted. Issue persists.

• Tried running sudo vmware-modconfig --console --install-all. Output will be located at https://paste-bin.xyz/12577

  The last section showed:

  Starting VMware services:
  Virtual machine monitor   failed
  Virtual machine communication interface   done
  VM communication interface socket family   done
  Virtual ethernet   failed
  VMware Authentication Daemon   done
  

What else should I try? How can I fix this?

There is one possibility I should point out, and that is either your internet is the cause or incorrect configuration on the VM.

Virtual machine monitor failed / Virtual ethernet failed

Disable secure boot via BIOS.The likely reason that's showing is that the verification checks on modern operating systems, conflicts with VMware algorithms, therefore giving those errors.

After you rebooted the host machine, with secure boot OFF, drop to shell and re-execute the command you tried:

vmware-modconfig --console --install-all

If this text appears:

It should take care of it. Just note that VMs are not the same as dual-boot. Almost all editing of the VM requires action from the host machine.

Disabled secure boot:

sudo mokutil --sb-state                      
SecureBoot disabled

But getting the same result:

Starting VMware services:
Virtual machine monitor                                            failed
Virtual machine communication interface                             done
VM communication interface socket family                            done
Virtual ethernet                                                   failed
VMware Authentication Daemon                                        done

Kernel version:

5.11.0-40-generic

Vmware version:

VMware Workstation 16.2.1 build-18811642