I am sorry ... as I was away for a week ... my friend had a same issue ... new machine (intel i5, 8gb ram, HP Pavillion) VB 6.0 ... I did exactly the same as I did to my machine and he is up and running. We tested the on/off/work multiple times to see that it works.
- Add a 2nd controller, the SATA:AHCI one. (the link is the first icon green in color at the bottom of the window in diamond shape with + sign)
- Now remove the disk (VDI) from the SCSI controller and add it to the SATA one.
- Boot the VM to make sure that everything is in order.
- Remove the SCSI controller altogether.
If I am not working for few people ... I am not sure about the reason ... but its quick 2 min step.