virtualbox.org

Just to confirm the results of this. My hard drive crashed and I am now in the process of replacing this and rebuilding my Virtual Machine. I did perform a number of checks on the drive and all said the drive was fine. So much for false hope.

You can mark this as the root cause.

Thank you all for your help. Really appreciated.

This is slightly OT but, yeah: chkdsk etc will be VERY wrong even if a drive is failing hard.

The only way to get the "real" status of a drive is via SMART. (smartctl on Linux, and I assume Windows has something similar available somewhere like Cygwin etc).

Raw_Read_Error_Rate etc is usually the critical one. I once had a drive that had >80K of them, and was corrupting data invisbily as well as only running at about 1/10th its "real" performance - but to chkdsk the drive was absolutely fine.