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I cloned my windows 7 installation on c: to external hard drive. I applied usb patch using pwboot and i could successfully boot into windows. But My problem is even though i am booting in to external hd the file reference and system path is pointing to c: on my internal hard disk. If i remove internal hd and boot it will get stuck at login screen. Is there any way i can force drive letter c: to my boot partition on external hd while booting from it.

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As I understand matters, in Windows 7 the drive from which Windows has booted is always drive C. So I suspect you're actually still booting the instance of Windows on the internal drive, although you may be using the boot loader from the USB drive. You may need to use bcdboot to create a boot loader entry pointing to the instance of Windows on the USB drive. – Harry Johnston Jul 2 '12 at 5:21
I also thought like that for the first time. I used easy bcd to install bcd to external and booted disconnecting internal hard disk. It booted correctly but the problem is with drive enumeration. i Suspect that windows enumerate internal drives first and then external. so even though i boot from external internal hard disk partition is detected as c:. I have found a solution but not tried it . Will try and if it work i wil let you know. – ichathan Jul 2 '12 at 9:51
The above link worked for me. I will post a tutorial soon. – ichathan Jul 2 '12 at 16:54
up vote 1 down vote accepted

I found the solution for drive letter conflict.Hope it may help someone. Please hit up if you liked it.

Here are the steps from scratch.

1.Install windows 7 to an internal hard drive.

2.After installation is complete copy the entire partition to external hard disk using easeus partition wizard.Preferably install os in c: of internal and copy the partition to starting of external hd. install bcd to external using easy bcd. donot forget to add the cloned partition to boot menu.

3.Apply USB patch using pwboot(important)

3.After that boot into external hard disk while internal hard disk is connected.

4.Internal hard disk will be detected as c. Booting will start from external hd partition but after os boot all file references will go to internal hd as it is detected as c:.

5.Note down the drive letter of cloned partition in external usb.say D:

6.Now disconnect internal hard disk and reboot into external usb. You will end up in desktop without any toolbar or wallpaper.

7.Press ctrl+alt+del to bring task manager then in run type regedit.

  1. In registry navigate to HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices

  2. Rename "\DosDevices\C:" to say "\DosDevices\B:"

10 Then rename "\DosDevices\D:" (where d: is the drive letter of windows installation in external usb.) to "\DosDevices\C:"

11 Reboot and enjoy windows 7 from external usb hdd.

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Don't forget that you can mark your own response as the chosen answer & should do so. – Julian Knight Jul 2 '12 at 20:26
I tried to do so. But it is showing "you can answer your question only tommorow" – ichathan Jul 3 '12 at 3:08

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