MacOS-Big Sur VirtualBox Error the virtual machine has terminated unexpectedly during startup with exit code 1 (0x1) This happens after updating into the MacOS Bug sur. And then trying to start the VirtualBox VMs,
Tried so far and no luck with below options,

Un-installed and re-installed the VirtualBox
Created completely new VM and tried
Re-installed Oracle_VM_VirtualBox_Extension_Pack-6.1.16

Anyone else came a cross with the same issue? any clue to resolve this would really appreciated.
This the the complete Error message

Failed to open a session for the virtual machine New Ubuntu.

The virtual machine 'New Ubuntu' has terminated unexpectedly during startup with exit code 1 (0x1).

Result Code: NS_ERROR_FAILURE (0x80004005)
Component: MachineWrap
This worked for me
sudo su
csrutil clear
reboot


Then uninstall (from the official uninstaller) and re-install VirtualBox
If prompted, go to System Preferences - Privacy - General and accept the extensions
Reboot