When VirtualBox is recently used to load a virtual machine (vmdk) that has been created, an error is reported for no reason. Mac OS Big Sur 11.2.3:

I always thought there was a problem with the creation of my virtual machine. Finally, I found that it was caused by the security mechanism of MacOS, and there was no good prompt in the virtual box, which led to this problem for many people. The following is the solution:

Enter system preferences and select “security and privacy” settings:

You will notice such a prompt at the bottom, or:

Just follow the operation and agree,

Don’t forget to enter the password first, and finally restart the computer to solve it ~