virtualbox.org

I have been changing my desktop every couple of years and moving along with Windows XP to Vista to 7 to 10...and VBox v3 to 4 to 5...and a few VMs. All my work files are on a separate, rugged, independently backed up NAS box. I want to keep all my VMs fully on the NAS so that I do not have to worry about losing or reconfiguring them every time I upgrade the Windows host. I see that VBox keeps some files in ".VirtualBox" and "VirtualBox VMs" folders under my Windows profile on the local C: drive.

Is it possible to reconfigure VBox to completely remove dependence of existing+future VMs on C: drive?

"Virtualbox VMs" is the default folder for new guests. You can point this default folder anywhere you want in the GUI Preferences, General section. All new guests will be in the new folder. Old guests will have to be moved if they're not OK where they are now. See Moving a VM

Have you tried installing on a different drive? Does that move the .Virtualbox folder? You might be stuck there if not, but re-registering the guests in a fresh host OS and Virtualbox is easy as pie, just double-click the .vbox file.

Running a guest or four off a network location will limit the disk data throughput to the network bandwidth. You'll probably run slow unless you have a wicked corporate network system between the NAS and your PC.