Hi everyone,
I'm aware this issue has been posted many times in the past, however i can't seem to get it to work. I have a set of virtual machines that a previous colleague has created and used with Gns3 and I have to work on them. However when I try to open the Gns3 project, I receive an error from Virtualbox. I have the folders of the virtual machines as he left them. When I try to add them via the Vitualbox GUI, I also receive the same error
A differencing image of snapshot {43abb85f-5a7b-415b-ae7a-06a979dba5db} could not be found. Could not find an open hard disk with UUID {0d38f15b-e8b0-443d-a7d6-aa920cffb6cd}.
I have tried editing the .vbox file multiple times but without success. That's why I turned to the experts. Could anyone help me with this issue?
Here's the .vbox file of one of my virtual machines attached.
It probably means that the VM is a linked clone, which means you also need the VM it's linked to, and you must register that VM first.
I have tried editing the .vbox file multiple times
That doesn't sound good. Left alone it's pretty much guaranteed to work. But after the vbox file has been edited multiple times by a novice then who knows. IMHO you should revert the VM to the state it was in when it last worked.
Another possibility is that you did not copy the complete VM folder.
That said, I'm have trouble making sense of the provided .vbox file: it uses snapshots but there is no sign of a media registry. AFAIK even if it started off as a linked clone, if it has snapshots then media was created and there should be a media registry.
What VDI files exist in the VM folder, or Snapshots subfolder?
Hi mpack,
Thank you for the fast reply. I always backup the .vbox file so the one that i sent you is the original. There are two snapshots in the snapshot folder (look at the image). You are right about the linked clones, my colleague probably used linked clones in gns3. Do you have an idea how i could find the parent VM?
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There is no direct way to find the original VM. All that VirtualBox cares about it is that the missing virtual drive UUIDs are registered, it doesn't care which VM or VMs do the registration.
I also asked about VDI files that exist in the VM folder? I.e. is there a base VDI there? If the VM is a linked clone then there should be no base VM.
Although there's no direct way to find the original VM, it shouldn't be too hard unless you have a huge number of VMs. It would have to be a VM with the same OS and a similar recipe. You can check the UUIDs of a drive by using File|Virtual Media Manager, or on the command line with "VBoxManage showmediuminfo <filename>".
p.s. Can you suggest why your colleague may have used linked clones? Frankly they're a recipe for a spaghetti mess of cross links, and backup disasters of precisely this kind. If I used them (and I prefer not, because it modifies the template VM) it would only be for short tests, then delete.
The only good scenario I've heard for them involved a teacher and a bunch of students. Obviously creating a linked clone in that scenario was preferable to a stand alone clone for each student. At the end of the lesson/course you just discard all memory of the linked clones: and since they're useless without the original VM, any students light fingered tendencies aren't a problem either.
If each clone was to have a long term independant life and store important data: they would be full and independent clones.
Hi mpack,
I am actually a student working on this project and my colleague is a fellow student who worked on the same project before me. We are trying to simulate a Network with a bunch of PCs connected together and observe the traffic + do some stuff. To do this we have to use virtual machines. However we can't use multiple independent virtual machines since this would affect performance and we don't have enough space in the host PC (our resources are limited) That's why we used linked clones since this option is available in the network simulation program(Gns3) which can create VMs(as linked clones) and use them as components . We are using Ubuntu 18.04 for all VMs. I installed Virtual box + Gns3 and I'm trying to add the VMs to Virtualbox so I can work with them but because of this error I can't. I think I have to look through all .vbox files to look for UUIDs right? Since there are many could you tell me which UUID is relevant in the vbox file?
Yes, you first need to establish what the parent media UUID is, and then find the VM that registers that UUID. The parent VM must be registered for linked clones to work on that PC.
Yes, you can then search every .vbox file, looking for the one which registers the parent media (the <MediaRegistry> section in the .vbox).
If there is a PC on which this still works then you should be able to find the parent media in File|Virtual Media Manager. You may have to right click any VDI and select "Properties" in order to get the VDI details panel to appear, but thereafter you can click on other VDIs and the properties panel will update: the info presented includes the media UUID.
Being a linked clone or not doesn't affect the performance of the VM, but it does of course affect disk space requirements.