Failed to delete snapshot...Hard disk has more than one child hard disk" (again)

[Bob Kosch]

Unable to merge differencing disks from snapshot created natively in the same version of VBox.

Screen captures and VBoxSVC log attached.

[Thomas]

I am also encountering this problem.

[Armand Welsh]

I have 4.1.0 as well. I have deleted all but one snapshot from one of my Virtual machines, and just one snapshot is causing this error for me too.

[Bob Kosch]

Anecdotally this issue, which was such an everyday occurrence in 4.1.0, has not yet occurred in 4.1.2.

Whether that's due to intrinsic improvements to shapshot algorithms themseslves, or due to the fact that the UI on Windows x64 no longer crashes regularly in the middle of performing snapshot operations, I don't know.

4.1.0 was, to be brutally honest, a bug-riddled, regression-filled "release" I'd rather forget.

[Bob Kosch]

Exact same issue occurs in latest version 4.1.2, for the same reason (a service crash right in the middle of performing Delete Snapshot operations, leaving orphaned files). Just not as frequently as the bug-riddled 4.1.0.

These quickly grow in size, making the usual "just delete the little one" approach, something which always struck me as an absolutely ridiculous suggestion, dangerous or impossible.

In VMM, the indented differencing disk is frequently not attached, while the non-indented differencing disk is attached.

What in blazes do you expect the average user to do here in order to collapse the state of the VM?

[Armand Welsh]

I have also noticed taking a snapshot from command line and forgetting to add --pause causes the vm to crash. I wonder if this is what is causing these bad snapshots. Either way I am still trying to learn how to delete my on lost snapshot image

[Bob Kosch]

The illogical paradox in the VMM GUI I described in follow-up(for which I have screen captures as absolute proof) reversed itself to the expected behavior with absolutely no action on my part.

Therefore I think it is unwise to trust the GUI at all, and may be safer to try to recover from whatever VirtualBox has managed to inflict on itself, something the average user encounters on a regular basis, something the developers evidently find it so hard to reproduce, by cloning the current-state vdi by UUID, detaching the original virtual disk, and reattaching the cloned disk.

[guntbert]

shows the unability to delete a snapshot on 4.1.2 r73507

[guntbert]

In my case creating and trying to delete the snapshot took both place on the same VBox version (4.1.2) - so the problem is definitely not fixed.

[dyle]

Here is the very same issue for VirtualBox 4.1.4 and it is pretty annoying.

But as I tend to delete the old snapshots and use the latest one, I rename the whole machine, make a clone, name the clone the original one and delete the former buggy machine. That helps in some cases though ugly.

[kenkyee]

This bug is possibly a dup of bug 7461.

Still happens with latest 4.2.12 if you run out of disk space. You'll get an orphaned snapshot.

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.