Unexpected incompatibility between V9.x and V10

During testing I have noticed an unexpected incompatibility between ATI v9.x and ATI v10. I would be interested to learn from other Forum members if they have experienced a similar issue.

Environment : Windows XP Professional SP2

Windows freezes on a system where the MBR on a system disk was previously created using v9.x and then subsequently the system partition is imaged and restored using v10. Windows will boot normally up until just before the user logon screen is displayed which means that the MBR is directing the boot sequence to the correct partition but at that point the files winlogon.exe and lsass.exe are not executing.

The solution is of course quite simple, namely, image and restore the MBR using v10 and the logon will proceed normally.

So as such this is not a problem, but it is unexpected as one would assume that an MBR that was imaged and restored by either v9.x or v10 would be absolutely identical (assuming no changes to the MBR data).