The VirtualBox 6.1 Extension Pack was a mature, battle-tested add-on that made the hypervisor competitive with VMware Workstation Player. It excelled at USB 3.0 and remote display. However, with 6.1 now unsupported, treat it as a – install it only to maintain existing VMs, not for new ones.
Oracle no longer provides public bug fixes or security patches for the 6.1 branch. virtualbox 6.1 extension pack
VBoxManage extpack install Oracle_VM_VirtualBox_Extension_Pack-6.1.50.vbox-extpack The VirtualBox 6
Here’s what made the 6.1 Extension Pack an essential component for any serious virtualization workload. with 6.1 now unsupported