Hi there O~

Just as a side-thought, could it be possible to identify the bad sector(s) of the disk and create a partition around it, kind of like a physical quarantine? Or does it not quite work that way?
Manufacturer's drive tools used to work that way, and create a new "recovery area". This would certainly not be detected by scandisk/checkdisk.

Back in the days of having to physically tell your system to park the HDD heads this was generally OK, as the damage was frequently minor physical problems caused by moving the PC without parking the heads first.

Today's HDDs are more sophisticated, so when you hit a problem like this it is generally fatal. Well, I certainly wouldn't recommend the continued use of such a drive

Also, why would the upgrade tell me that there is a bad MBR and it can't continue, but the upgrade rollback returns me to working order? I thought the MBR was in a fixed area on the HDD. Doesn't make sense to me, unless I am misunderstanding the whole thing.
The "upgrade" is effectively going to reinstall, so it checks the drive condition. Rollback is just an internal recovery so does not do this.

[QUOTE][Oops, forgot to mention that Scandisk doesn't report any bad sectors, it just skips over 20% of the free space.
That's a bad thing, isn't it?/QUOTE]

Strange, but I have noticed that.............. I thought it was possibly my imagination but it does seem to finish a lot faster than it starts off?

I really feel the need to do a bit of research on this, as you have raised a question to which I do not have a definitive answer.

I suspect that when Scandisk/Checkdisk hits the area that still has the original manufacturer's "pattern" on it, it skips the testing. As a technician I would not find that acceptable in a "proper" diagnostic tool. However, I can see Microsoft's viewpoint; in that these are "user tools" to be employed when you have problems, or to avoid them. So, you are only interested in the part of the drive that you have been or are still using?

The never used part represents: "joys still to be experienced"

That is a complete guess by the way

I do have a matching pair of "virgin" drives I can experiment with. I am thinking of:

1. Load OS onto a drive as it comes out of the box.
2. Nuke the second drive with DBAN or Eraser and load the same OS
3. Run Checkdisk, and see if there is a difference.

If I overwrite with random data, it should look different from the manufacturer's "pattern", I would have thought?