VirtualBox: Failed to open a session for the virtual machine

When encountering the error “Failed to open a session for the virtual machine” in VirtualBox, there might be an easy solution.

Error

Failed to open a session for the virtual machine Zorin.

Unresolved (unknow) host platform error. (VERR_UNRESOLVED_ERROR).

Result Code: E_FAIL (0X80004005)
Component: ConsoleWrap
Interface: IConsole {6ac83d89-6ee7-4e33-8ae6-b257b2e81be8}

Solution

1. Open the command prompt as an administrator:
   Press “Win + R” to open the Run dialog, type “cmd” and press “Ctrl + Shift + Enter“.

2. Check if the hypervisorlaunchtype is set to auto or is missing at all.
   bcdedit

3. Turn the hypervisorlaunchtype off and restart the computer:
   bcdedit /set hypervisorlaunchtype off

4. Turn the hypervisorlaunchtype on again by setting it to auto and restart the computer:
   bcdedit /set hypervisorlaunchtype auto

5. Launch VirtualBox