Environment: Win10 - 1903
Q1: After installation Hyper-V, Virtual box mounting new VM, can not start
A1: Uninstall Hyper-V (non-essential)
Administrators running ps / cmd bcdedit / set hypervisorlaunchtype off (prohibition of hyper-v)
Restart the computer resumes
Q2: After uninstalling Virtual box to install Hyper-V, the same error: The hypervisor is not running
A2: administrator runs ps / cmd bcdedit / set hypervisorlaunchtype Auto
Restart the computer resumes