PDF of article How to install Microsoft Windows 11 on VirtualBox!
Refer: https://blogs.oracle.com/virtualization/post/install-microsoft-windows-11-on-virtualbox

Technical notes, and other ideas.
Error in VirtualBox VBOX
These are the steps that VirtualBox takes when it writes a new Vbox file. Each step is contingent on the last one being completed without errors.
Have not tried these yet
The error that comes after the corruption of the vbox XML file is usually caused when the system locks up; thus preventing the virtualization software from finalizing the writing out to its file of configuration. The error probably implies that the <VirtualBox> opening tag on the line 2 of the file did not have any corresponding </VirtualBox> closing tag at the file’s end.
The fastest method of finding out if this is exactly what has caused the problem in your case; you can locate your vbox XML file for the Guest Operating System, whose home directory location is inside the folder of ‘VirtualBox’ in the ‘Machines’ folder in the ‘Name-of-Your-Guest-OS-Directory’ folder, saved as ‘Name-of-Your-Guest-OS.xml file’
The cause of the problem and the emergence of the error message could probably be simply that the XML file was badly corrupted whose repair process is easy and quick and might take only a minute to be repaired.
Refer: https://www.bitrecover.com/blog/repair-corrupt-virtualbox-vbox-file/
Download Notes: [ repair-corrupt-virtualbox.pdf ]
Refer: https://forums.virtualbox.org/viewtopic.php?f=6&t=75068
These are the steps that VirtualBox takes when it writes a new Vbox file. Each step is contingent on the last one being completed without errors.
Refer: https://www.techprevue.com/virtualbox-inaccessible-file-not-found/
iii) Out of the above-mentioned issues, "File not found" is the most common one. During that situation, you can go to the location of the file. One of the possibilities is that you might find suffixes after the extension .xml for eg. .xmlmog or .xmlemf. So if you are looking for file abcd.xml it actually exists there by name abcd.xmlemf and hence your system was unable to find the file abcd.xml because it did not exist. Now what you can do is, simply copy the file and paste it in the same location and rename it with extension just .xml. This would solve the issue of an inaccessible "file not found" error.
There are some issues installing VirtualBox 6.0 that's not in the basic Ubuntu repositories. Easiest install is from the software center or apt-install.
$ sudo apt install virtualbox virtualbox-ext-pack
Getting USB Support to Work
Refer: https://www.techrepublic.com/article/how-to-enable-usb-in-virtualbox/
You will need to add your username to vboxusers group
open a terminal
sudo gedit /etc/group
vboxusers:x:125:mruckman
reboot Ubuntu to make sure it picks up the new changes
You will also want to install VBoxGuestAdditions_4.1.2
mount the ISO image inside the virtual appliance
You can download various versions of the software here:
http://download.virtualbox.org/virtualbox/4.1.2/
Turn off "Enable absolute pointing device" to have better response during shutdown and reboot.
When the virtual appliance is turned off, do the following:
Settings, System, uncheck the "Enable absolute pointing device"