The reason why the virtual machine cannot be started

• Possible reason 1:

  Find the virtual machine installation directory, and if you don’t remember, look for the error message. As above, mine is D:UsersDocumentsVirtual MachinesUbuntu 64, and then

  Delete all the .lck files inside, and you can start it.

  Reason: The virtual machine will create corresponding files when it is running, that is, the .lck lock file will be automatically generated in the installation directory of the virtual machine. This is the disk protection mechanism that comes with the virtual disk (.vmdk) of the virtual machine to prevent multiple Simultaneous access by virtual machines to the same virtual disk results in disk modifications, data loss, and performance cuts.

  If the virtual machine exits normally, it will be automatically deleted when it is shut down. If it is a forced shutdown, it is an abnormal exit, and the virtual machine has not yet been deleted, which will affect the next normal startup.

  Possible reason 2:

  When starting a virtual machine in VMware Workstation prior to version 12.5 on a Windows 10 host with Credential Guard or Device Guard enabled, a blue diagnostic screen (BSOD) is displayed.
  You see errors similar to:
  VMware Workstation and Device / Credential Guard are not compatible. After disabling Device/Credential Guard, VMware Workstation can be run.

  Reasons:
  1. The reason for this problem is that Device Guard or Credential Guard is not compatible with Workstation.
  2. The Hyper-V in the Windows system is not compatible.
  Solution:
  Step 1: Disable Device Guard or Credential Guard:

  Disable the Group Policy setting to enable Credential Guard.
  On the host operating system, right-click Start > Run, type gpedit.msc, and click OK. The Local Group Policy Editor opens.
  Go to Local Computer Policy > Computer Configuration > Administrative Templates > System > Device Guard (or: Device Guard) > Enable Virtualization Based Security.
  Selection is disabled.
   
  Go to Control Panel > Uninstall a program > Turn Windows features on or off to turn off Hyper-V.
  Choose not to restart.
  Step 2: Shut down Hyper-V by command (closing Hyper-V in the control panel will not play a decisive role, you must completely shut down Hyper-V) 

          Run Windows Powershell (Admin) as administrator (Windows key + X)

          Run the following command and restart your computer:

  bcdedit /set hypervisorlaunchtype off