Failed toopen session

[khschulz]

I deleted an older snapshot - created from an older version - and now cannot boot anymore.
The error is:
Failed to open a session for the virtual machine Windows7.

Parent UUID {2671d261-3ba5-4e3a-a8df-aab4b5c13da6} of the medium '/Users/khs/VirtualBox VMs/Windows7/Snapshots/{756f0cb9-ee2e-4da1-8e66-8b9c4d2ec830}.vdi' does not match UUID {57b9eb09-f4f0-489b-aaeb-9f03dec4cc9b} of its parent medium stored in the media registry ('/Users/khs/Library/VirtualBox/VirtualBox.xml').

Result Code: NS_ERROR_FAILURE (0x80004005)
Component: Medium
Interface: IMedium {29989373-b111-4654-8493-2e1176cba890}


How can I fix the issue?

TIA

[khschulz]

Well the error means exactly what it says : the file couldn't be found, in this case the VDI of the VM. So I would double check and triple check that the pack of the error message is valid.

Is your answer related to my posted problem (first thread)?
It seems that his error is not related to my post.
TIA

[noteirak]

You're right, I didn't notice the change in username.
I'll split the conversations.

[noteirak]

Please post a screenshot of the Media Registry, at the disk of the VM with all childs expanded so we can see.

Did you delete the file directly or did you remove the Snapshot from Virtualbox Manager?

[khschulz]

I removed the snapshot from the Virtualbox Manager

[mpack]

I note that the error message refers to a media registry stored in VirtualBox.xml, which VirtualBox stopped doing years ago.

Are we missing parts of this scenario? For example, did you already try restoring individual files from backups? - details please if so. At the moment the error message doesn't appear to match the problem setup.

Also, "I removed the snapshot from the VirtualBox manager" is somewhat ambiguous: it allows multiple interpretations. The correct way to delete a snapshot would be to go to the VM settings, click the snapshots button, highlight a snapshot, and click "Delete snapshot". A wrong way to remove a snapshot (but still using the manager) would be to go into File|Virtual Media Manager and release and remove a vdi file that was still needed by a VM. Please say explicitly which of these you did.

[khschulz]

Sorry for the misleading reply.

I removed the snapshot using the VirtualBox Manager, selecting the Virtual Machine, Snapshots Tab, and select an older snapshot (~20 days ago). I currently can see two versions - another snapshot from 15 days ago and the current state (changed).
I have not attempted any restore yet.

[mpack]

I have not attempted any restore yet.

I recommend making a complete backup of the .VirtualBox and VM folders before you try any kind of restore.

Another thing you can try is downloading CloneVDI (as its a Windows app you'll also need Wine from the Apple store), and use it to investigate the UUID links between the current state and parent VDIs, back to the base VDI. If you can construct a complete chain of files (all in one folder) then you can clone the current state VDI to create a flat clone VDI to build a new VM around (*). This will be safer than attempting a restore.

(*) Do not attempt to mount the clone in the original VM. The new VM should however be an exact match for the old VM recipe.

[khschulz]

thx for the suggestion.
I will try the CloneVDI - have access to Windows boxes.

[khschulz]

The fix was rather easy.
It was necessary to delete the *.vbox file, to create a new one using the existing *.vdi file.
It don't yet what caused the corruption in the original *.vbox file but will let the group know when done.

[mpack]

Your solution is not actually a real solution. If you built a new VM around the base VDI then you lost all of the data stored in the later snapshots. That may not be significant to you, but will be for others.

[khschulz]

I realize that - that why I kept a copy of the broken VM to see what caused the issue and how to fix it.
The CloneVDI did not help but after I was able to get the VM booting again I received an error with the Media Manager - still pointing to the non-existing snapshot.