How do I move an OS from an HDD F-drive to a SSD D-drive and have everything pointing to "F:\" now point to "D:\" instead?

Goal is to have a dualbooted system, with Windows 7.0 as the first partition on the SSD and Win 10 on the 2nd partition of said SSD. Win10 ran on a HDD, which now will be used to store data aka content files. I use a graphical BCD editor to make the startup menu, which is in the Win7 style, not the fancy Win10 style

This is different from the usual SSD replacing of a HDD, where the OS from a C-partition on a HDD is moved to the C-partition on a SSD.

Problem isn't the moving, cloning or booting. It has been cloned, and the two OSes boot up just fine, provided the HDD stays in the laptop. Yes, that means I have two duplicate Windows 10 OS on my computer. The problem is that if I physically remove the HDD with only the SSD remaining physically in the computer, the new OS doesn't boot up as it was, but as a fresh installed Win10 with all settings gone.

My guess is that large portions of the new OS on the SSD still point to to the partition where the old OS is still sitting. The OS on the new SSD partition does get flagged by Windows as the boot partition, though.

So my question is: How do I make it so that the OS on the new partition can boot up "solo", so without the HDD still physically in the DVD bay?

What I tried:

When the duplicate Win10 on the SDD was booted up without HDD inserted, as D-drive and there was no C-drive present, I tried to edit the registry. Specifically, a Search and Replace of all "C:\" strings to "D:\". That didn't work, because the error message said I didn't have full permission to do that or the drive was busy. The result when I rebooted was a Win10 appearing as a fresh install. Upon reboot WITH the HDD inserted, it was back to normal, which suggests that it points towards the original Win10 partition on the HDD.

EDIT Several screenshots

boot from C-drive the DiskMgmt view just SSD: boot-CC-drive-DiskMgmt just SSD

boot from C-drive the Explorer view just SSD: boot-CC-drive-Explorer view just SSD

boot from C-drive the DiskMgmt view with HDD inserted: boot-CC-drive-DiskMgmt w/ HDD inserted

boot from D-drive Win10 the Explorer view with HDD inserted: boot from D-drive Win10 the Explorer view with HDD inserted

boot from F-drive (makes itself C-drive) Win10 the DiskMgmt view with HDD inserted: boot from F-drive (makes itself C-drive) Win10 the DiskMgmt view with HDD inserted

boot from F-drive (makes itself C-drive) Win10 the Explorer view with HDD inserted: boot from F-drive Win10 the Explorer view with HDD inserted

  • How did you even manage to install Windows in a way that the system partition isn’t C:? Or are you looking at the drive from another OS? Because only the drive letters the OS itself sees count.
    – Daniel B
    Mar 11, 2020 at 12:42
  • that surprised me too, so I don't know. usually, the booting OS gets C:, unless it is Win 7, which kind of doesn't care. But now, for the first time, I booted Win10 from "D:\" and it stays like that. Mar 11, 2020 at 12:46
  • Can you post a screenshot from Windows Disk Management? (right-click Start button and select Disk Management)
    – gronostaj
    Mar 11, 2020 at 13:19

2 Answers 2


You can't. Not without re-installing Windows that is.

What you MAY be able to do is to fake it.
If D: and E: are otherwise identical: Assign E: as second drive-letter to D: and give the old E: drive another drive-letter.
Chances are that you can't do that because the E: is permanently "in-use" and attempting to force this crashes the running Windows.
Best possible chance to make that work is booting the Windows 10 in "Safe Mode" and then start a CMD prompt as "Administrator". Make sure the CMD prompt itself doesn't have E: as current drive and then use diskpart to re-assign the drive-letters.

If it works it still leaves you with D: and E: but both pointing to the SSD and you should be able to re-purpose the HDD then.

  • I don't think OP actually wants to change the drive letter. They want to make the computer bootable with just SSD, so they cloned HDD partition to SSD, but their boot configuration is still on HDD so HDD must be present. Drive letter is probably an unimportant detail.
    – gronostaj
    Mar 11, 2020 at 13:03
  • @gronostaj He explicitly stated in the question that the SSD partition is listed as BOOT by Windows. And I'm thinking, as this is a dual-boot the bootloader is actually on C: and is possibly MBR style, not UEFI.
    – Tonny
    Mar 11, 2020 at 13:15
  • It's a cloned partition, so it probably has the same filesystem UUID. My bet is there are now 2 partitions with this UUID, but bootmgr (installed on HDD) finds the SSD one first because SSD is on first SATA port (HDD is in DVD bay) and bootmgr enumerates partitions in this order.
    – gronostaj
    Mar 11, 2020 at 13:19
  • First comment of @gronostaj is correct. However... to make matters more complicated, i think i CAN boot from the FIRST partition on the SSD, which is Windows 7, without the HDD physically present. i will check that now to make sure.... Mar 11, 2020 at 13:53
  • @HeccateNewb Yes, please check that. That would confirm that the first part of the bootloader isn't on that HDD.
    – Tonny
    Mar 11, 2020 at 15:07

Boot the cloned Windows and make sure that it is the OS from SSD. 'Safely' remove external devices such as USB Thumbdrives. Open Command Prompt in elevated mode and write regedit. Search for HKEY_LOCAL_MACHINE\System\MountedDevices Delete all entries except for (Default). Also remove your HDD if it's not in use and is hotswappable, otherwise next step Shutdown Computer, Remove HDD Reboot and select OS Windows will remap the letters for current OS as C:, every other partition will be invisible but you can of course manually initialize them in Disk Management and give them identifiers.

Also see: Cloned Windows 10 hangs in black screen with cursor

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