Recently Oracle has released the new version of VirtualBox and I installed it on Bigsur. Finally, I could run VirtualBox on BigSur.

The following are what I got when I tried to install Ubuntu on VirtualBox.

In my case, the issue was the security settings. As you know, macOS gets more and more strict.

Here are what I did to work out the issue I had.

Step 1 Run the command

$ sudo kmutil load -b org.virtualbox.kext.VBoxDrv</span>

Step 2 Allow VirtualBox/Oracle to have permissions

System Preferences > Security & Privacy
Unlock and Click Details and checked Oracle

Privacy tab > Full Disk Access
Add VirtualBox

Step 3 Reboot macOS

Just restart macOS and run VirtualBox