я взял эту инструкцию отсюда — https://forums.virtualbox.org/viewtopic.php?f=1&t=48258
My attempt at a step by step.
1. Shut down VirtualBox, back up your <userdoc>\.VirtualBox\VirtualBox.xml file.
2. Find your existing «Virtualbox VMs» folder, and copy (not move) the whole folder with contents to your new drive E:
3. Run VirtualBox, then for each VM in turn :-
3.1 Right click the VM name and select «Remove» from the popup menu. Answer no to the «physically delete files?» question.
3.2 Select the Machine|Add.. menu item, navigate to the VMs new location on drive E:, and select the .vbox file.
3.3. Repeat for any remaining VMs.
4. In File|Preferences, set the default machine path to «E:\VirtualBox VMs»
5. Test each of the VMs. Only after you are sure they all work, delete the old VM containing folder, i.e. delete «C:\VirtualBox VMs».