Migrating win7 Machine from Lion to Mountain Lion

[1ndivisible]

I have a laptop running Lion with Virtual Box installed and a VM containing Windows 7. It works great. I've just picked up a new laptop running Mountain Lion(10.8.1) and tried to migrate my VM over. I Virtual Box on it, then created a new VM using the wizard, choosing 'Use existing hard disk'. When I start the VM however, I get the following:

Windows failed to start. A recent hardware or software change might be the cause.

I can choose either Launch Startup Repair or Start Windows Normally, but in both cases Windows doesn't start and I end up back at this screen.

Can anyone offer any advice as to what I'm doing wrong or how I can troubleshoot this?

Thanks in advance.

[michaln]

You probably changed something in the VM settings. Of course only you can know what it was...

Note - in these cases, it is highly advisable to use export/import or (if both machines use VirtualBox 4.0+) simply copy the VM's directory to the new system. That way the VM settings are preserved.

[1ndivisible]

Thanks for the advice. Away from my other laptop now but I'll give that a go tomorrow.

[1ndivisible]

@michaln That did the trick. Thanks again.

For those that follow:

Had to change the machine UIDs in the registry. First time I ran the VM I got an error saying the machine UIDs in ~/Library/VirtualBox/VirtualBox.xml didn't match the VM's UID, giving me the expected UIDs in the error message, so I closed Virtual Box and its crashed VM, opened ~/Library/VirtualBox/VirtualBox.xml, and replaced the UIDs with the expected UIDs, then ran Virtual Box again and started the VM.