If you look at the CLI suggested in comments
https://www.virtualbox.org/manual/ch08.html#vboxmanage-clonevm
there is a flag for that there.
Silly GUI, I definitely would like it to remember what I last did. I use to do that I think in Version 5, but 6 it started changing the network info by default on Clones.
--options keepallmacs
This page shows a usage example
https://askubuntu.com/questions/510182/how-to-automatically-clone-a-vm
cd /VM_Storage
vboxmanage clonevm ImportantVM --name ImportantVM-02 --options keepallmacs --register
[ Note the register flag is pretty important to avoid more trouble later - see below ]
Of course if you're on windowz it's probably not in your shell's 'path', which you could fix, or you want to call this more directly via (probably in a script or something?)
"C:\Program Files\Oracle\VirtualBox\VBoxManage.exe"
Oh but you won't see it in the GUI so you need to import or launch via CLI so that is also kind of annoying, again it sure would be better if it remembered my last setting in the GUI.
Maybe you want this in the background/headless at some point too
VBoxManage startvm "Ubuntu Server" --type headless
but that actually will have an error
VBoxManage.exe: error: Could not find a registered machine named
It seems you need --register in the clonevm command, maybe a little late for that so how to register?
Apparently you need to use registervm for that. Alas it seems that it won't know where to look even from that directory via relative path so then you'll need to either set
vboxmanage setproperty machinefolder /path/to/vm_directory/ or include the full path when registering. BTW there is also an unregistervm command. Oh wait... Unfortunately it still doesn't help... so you'll need the full path to register it.
I guess it's better to remember the register flag during clonevm command (I've changed it above to avoid trouble for people checking this nightmare out).