virtualbox.org

I just created a new VM and noticed that there's an extra file in the VM folder ending with "-1.15-windows.vbox"

this doesn't exist on my old VMs. and it doesn't appear to be edited anymore after the initial setup.

i couldn't find any specific discussion about it from searching.

could anyone explain what this file does? and do i need to keep it?

thanks!

I have those in some of my guests, too. I'm not certain, but I think it's the old copy of the guest's .vbox file when the .vbox format requires an update to match a new version of Virtualbox. I think it is not needed anymore. But the safest thing is to put it somewhere safe not delete it, until a year passes and the guest runs flawlessly dozens of times. Or it's just a couple kB, leaving it where it is would be safest.

Exactly what Scott says. I believe the special backup is created whenever VirtualBox detects a format breaking version change. This allows you to go back to the older VirtualBox version if you wanted to.

Incidentally, it's using the internal version numbering system, which I think is about the version of the config format, not the VirtualBox version.

Yes, it's the version of the config file format, e.g.:

VirtualBox.xidl file wrote:

<desc>Settings version "1.15", written by VirtualBox 5.0.x</desc>
<desc>Settings version "1.16", written by VirtualBox 5.1.x</desc>
<desc>Settings version "1.17", written by VirtualBox 6.0.x</desc>
<desc>Settings version "1.18", written by VirtualBox 6.1.x</desc>

VirtualBox tries not to use the newest version if possible. If you create a new VM in VirtualBox 6.1.8 without the newest features, it still creates a version 1.5 config file. If you use Nested Virtualization for example, it creates a version 1.7 config file at least.