Installation dependent on two hard drives?


New Member
I wonder if someone can tell me what's going on here.

I installed Windows 7 Pro (64 bit Upgrade edition) tonight. I have two hard drives in this system, one of which is old and has a Windows XP install on it. I was planning on retiring that drive, but I'd heard that if I kept in the computer while installing Win 7, the installer would recognize it as a valid upgrade platform and let me smoothly install onto the other hard drive (a newer one).

Well, that much seemed to work. I installed the program and entered my serial number and everything is working fine... except that when I went back into the computer and removed the old hard drive, suddenly when I tried to reboot it was complaining that there was no system disk installed.

I wondered if I'd somehow accidentally installed it on the wrong drive (even though I was sure I hadn't), so I tried taking out the new drive and putting the old one in alone. This time it somehow recognized a Windows 7 installation (giving me the option to boot between "An older version of Windows" and Windows 7) but when I tried to boot it complained that a device is missing.

I put both drives back in and everything works again. So it seems that this installation requires both hard drives to be in the machine, but I don't understand why. Is there something I can do to get rid of the old drive for good?

Joe S

Excellent Member
The master boot file is on the drive with XP. Do some searching here I'm not sure how to fix it but it. It's been discussed before. Why not just leave the old HD there with XP in case you run into some old program you need to use.


Excellent Member
Microsoft Community Contributor
Yes, you can get rid of the old drive. During your install, the Win 7 boot files were put on the active partition on the XP drive. I say this assuming the situation is as it seems.

You can get the Win 7 drive to work if you use Disk Management to set the Win 7 partition to active. Then remove (or set to lower priority in bios) and run the Startup repair using the Install DVD. It will take 2 or 3 times for the repair to complete all needed conditions.

You can also use another command to put the boot files on the Win 7 partition, but you will still need to make the Win 7 partition active for them to work. After you do that, use this command and substitute the Drive letter for the Win 7 partition while you are booted into Win 7. I will assume it is C: for this.

Open an administrative command window and type:

bcdboot C:\Windows /s C:

Hit enter after and wait for it to finish. Then close the window, remove the other drive and reboot.

If you want to take a picture of your Disk Management window using the snipping tool and attach using the paper clip, it might help confirm the directions.


New Member
Thank you both. Setting the partition to active and running startup repair three times did the trick.

Is there any chance that this hiccup is going to cause me any long-term problems? It's not like it would be a big deal for me to reinstall Win 7 at this point.


Excellent Member
Microsoft Community Contributor
The only two files this affects are the two mentioned. If you would like to change the drive letter of the Win 7 partition, or move it to another location on the drive, if you were willing to reinstall, it might be a good time. If you decide later to move the partitions around, there is always a danger of data loss or worse.

Just make sure you do not have the XP drive installed and set as first priority in the bios, unless you want to dual boot.

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