virtualbox.org

I have a working XP Pro Guest, hosted on 3.0.8.r53138 on XP Pro Host.
When I take a snapshot, the guest is unbootable - 'A disk read error occurred Press Ctrl-Alt-Del to restart'
If I delete the snapshot, it works again.
Absolutely repeatable, in that I cannot make a snapshot of the VM.
Anyone else seeing this?
By the way, I deleted and re-created the VM, using the original disk. The problem persists.

You could try unregistering and then re-registering the virtual disk.

What type of virtual disk is it? (i.e. VDI, VHD, VMDK).

Unregistering the disk and re-registering had no effect.
It is a VDI disk.

Maybe create the snapshot with the command line VBoxManage and see if there are any error messages. If that works, then try a VBoxManage clonehd to see if the Current State can be read correctly by VirtualBox (it is the Current State that your VM can't read when it says "a disk read error occurred...").
Use the instructions here starting 'To clonehd the Current State of a disk'.
http://forums.virtualbox.org/viewtopic. ... 99#p103299
See if there are any error messages.

No messages during snapshot creation.
No messages during cloning.
Added new media to VirtualBox and created a new VM to boot the cloned image, same error message.
Any more suggestions?

VBoxManage clonehd or CloneVDI the base VDI and see if that fixes anything?
Boot a Live CD and take a new image of the VDI (only dd ever worked for me) and turn that into a new VDI with VBoxManage convertfromraw?
Reinstall VirtualBox?

Curiously enough, a different VM (an ancestor of the problematic one) has no problems with snapshots.

By ancestor, I mean I have already cloned the other one and done more to the clone. The clone is the one that is having snapshot problems.

Hmmm... thinking along those lines... maybe my snapshot is referencing the ancestor in some way... did I clone the descendant correctly? I must have otherwise VirtualBox would complain when I tried to add the media. VBoxManage showhdinfo shows reasonable data...

Cloning the problematic disk using clonevdi resulted in a clone disk which was unbootable, in the same way as the 'snapshot' of the original is unbootable.

Another edit: I have the same VM disk image on a Gentoo Linux (Intel) with the same version of VirtualBox. Same Snapshot problem as Windows XP.

It would appear it's VirtualBox related, now I need to figure out how to identify where the problem lies. Any suggestions on commands to run to 'dump' info on VDI?

Looking at the VDI tree with Virtual Media Manager might show something (or not). Look for the 'Attached to:' value for each VDI and child {hexUUID} file.
Perhaps post your (abbreviated - remove ExtraData and Hardware sections) VirtualBox.xml and <VM>.XML files for inspection?

As requested. Config files and a showhdinfo of the disk image, in question.
Note my earlier edit, this is happening on both Windows and Linux.

One thing I notice on my Linux version, that my Snapshot directory has a space in the name, whereas the parent disk image has no spaces.

Wondering if that is significant. Maybe not, as I have another Windows XP VM (which is actually a descendant of the problematic one) which also has snapshots of with the same directory names...

No Snapshot. With Snapshot. Really struggling to extract info which may help diagnose this.

...Lyall

I see nothing alarming in the XML files and spaces in the directory names should be OK.

Problem solved.

Created a new disk, booted Clonzilla and cloned the disk.

Cloning the disk with VBoxManage clonevdi did not work.

...Lyall