virtualbox.org

No, VBox doesn't check whether it actually needs the parent. All it cares about is what's referenced by the media registry, and what's referenced by parent-UUID links. The VM wont start unless all referenced media is present.

Exactly! If the snapshot file was used but the parent never registered in any way, why wouldn't it work?

noteirak wrote:I would be interested in the sizes of the main disk and the snapshot

The base disk has a size of 18.4GB, the snapshot is 4.85GB.

The correct base disk wasn't linked at all since I based my first attempt on a machine with no snapshots and didn't know about the implementation or markup of these. What might be possible is that I missed some of the linkage to the original disk of the old machine I took the markup from (or its name and that helped in finding the older machine's disk), but that wouldn't have been in a correct snapshot syntax as stated above: Would VirtualBox complain in this case or might it try to fix the problem and merge the two links, maybe try to base the snapshot on the base disk of the old machine? I sure must have missed some naming because the resulting configuration was written over the base disk of the old machine. As stated in another post this older machine configuration was very similar to the correct base disk, same OS even with similar installs. The resulting disk of that corrupted combination had a size of about 30GB which thus surely would hint that there is more to it than only the snapshot.

noteirak wrote:Exactly! If the snapshot file was used but the parent never registered in any way, why wouldn't it work?

I assume you mean why would it work. I believe the parent must be registered, it simply wouldn't work without that. However it must be registered elsewhere: in another VM, or in VirtualBox.xml. We don't have enough information to settle that.

mpack wrote:I believe the parent must be registered, it simply wouldn't work without that. However it must be registered elsewhere: in another VM, or in VirtualBox.xml. We don't have enough information to settle that.

You can get more information: It was not registered in another VM, and I don't see how the snapshot should have become a "clone". There is no VirtualBox.xml in the VirtualBox folder and VirtualBox has no folders in the user application data - where can I find this file? noteirak's suggestions so far seem to make much more sense. But what about my question as to how VirtualBox would or would not try to resolve an ill-configured *.vbox-file?

VirtualBox will not try to solve a problematic .vbox file, it will mererly report it is not right and the VM will be labeled as innacessible.