Windows 7: Using a HDD Clone

I have two SATA HDDs on my Win 7 PC. The first is the system boot drive and the second is a clone of the first made with Paragon Partition Manager 11. The clone even has the same signature as the first which has resulted in Windows 7 marking the drive inactive and not assigning drive letters. All of this is OK, if my first drive failed, I could replace it with the clone and Windows should see it as a new first drive, mark it active and assign appropriate drive letters.

But, since any SATA HDD can be used as the boot drive, not just the first in the chain, I have been thinking about how to use the clone as the boot drive as a check. I came up with this procedure and would like to know if it would work.



1. Use diskpart to change the signature of the second drive (The clone.) back to it's original value. Win 7 should then mark the drive active and assign drive letters.

2. Use Win 7 Disk Management to remove the drive letter from the first partition (System Reserved) which normally doesn't have a letter assigned. (Maybe Win 7 won't assign a drive letter to this partition.)

3. Use the PC BIOS to set the second drive as the boot (System) drive.

4. Boot the PC to the clone drive.

Any comments or suggestion will be much appreciated, Jim

I'd guess that your current "active" partition is System Reserved?

And I assume the cloned drive also has a System Reserved partition?

I think you can use diskpart to directly mark a partition as active.

You might want to look here:

Partition - Mark as Active

I'd be interested to see how your test works out.

Are you saying that you have a cloned HDD installed at the same time as your original and your system boots ok? If so I'm surprised.

My understanding is that in the boot process the disk signature is also stored in the BCD, as well as the MBR, to identify the disk that contains the windows loader (winload.exe). You can end up with the situation where the active system reserved of one disk is loading windows on another disk. I think this is not a good situation.

Normally I would have either the original OR its clone installed at any one time to avoid a disk clash.
BUT I would also be interested in the results of your test.

When Paragon made the clone of "C", it also changed the signature of the clone to the signature of "C". So, there was a "signature collision" and Windows set the clone offline and didn't assign any drive letters. So, no problem, the system boots just fine because the clone is ignored.

But, since any sata drive can be the boot drive, not just the first in the chain, I wanted to try and boot from the clone without having to physically replace the original with the clone.

Regards, Jim

If the objective is to do a simple test to see if the clone works, disconnect the the C:\ and reboot.

physically unplug the cables.

I just completed the test I outlined in the first post. I used diskpart to change the disk signature to it's initial value, put the disk online and set the System Reserved partition to active. Windows assigned letter "D" to the System Reserved partition and "G" to the Windows partition. The system continued to function normally. And it rebooted with no problems.

So, I then used Disk Manager to remove the drive letter from the System Reserved partition and change the drive letter of the Windows partition to "D". The system continued to function normally. And it rebooted with no problems.

Next, I used the PC BIOS to change the boot drive to the clone. The system booted normally with no problems. And Windows changed the drive letter of the System Reserved partition of the "anti-clone" to "G". So, I aasume the system has booted from the "D" drive.

I need one more test to verify that "D" is the boot drive and that the Windows partition on "D" is the one being used. I think I can use the PC BIOS to remove the "C" drive from consideration in the boot process.

I will update this post when I complete that test.

Regards, Jim

You seem to get hung up on the lettering. Whether the System Reserved partition has a letter or not is pretty irrelevant. Und the boot partition (not active partition) should automatically assume the letter C once running - regardless what the letter was before - as viewed from another boot.

I can't find the MS reference now but I know at one stage Windows 7's solution to a disk signature clash was to change one of the disk signatures causing booting grief. I ran something like your experiment ~ 6 months ago and Windows changed the disk signature of one drive.

More recently I have bought identical WD external USB HDDs and they come out of the factory with the same disk signature. When both are connected, the second is is not recognized (appears "offline"). I change the signature of one and everything is fine and both are recognized. I suspect Windows 7 may have changed their disk clash strategy in an update.

Back to a sensible objective: A fast startup "Clone"
I have one in a HDD bay unplugged. When needed unplug the current HDD and plug in the "clone". Having the second one spinning causes unnecessary wear and tear on the drive and consumes energy.

I was trying to avoid having to physically remove a HDD to use the clone.

But, after some additional testing, it appears that the Windows partition on the disk in first position, P0, is still being used even though P1 is specified as the HDD to boot in the BIOS. Maybe as someone suggested, P1 may boot to the P0 Windows partition. Or maybe P1 is not seen as bootable and the system goes to the next device in line which is P0.

I don't see any way to do any more testing without physically removing P0 because diskpart will not allow P0 to be taken off line.

Anyway, it was a learning experience.

Regards, Jim

Just a quick edit: I used Windows PE and diskpart to successfully take disk P0 (C) off line, then rebooted. Windows placed P0 back on line and booted it.

Regards, Jim