Drive letter assignment wrong on install.

Posted on 2006-10-20
Last Modified: 2008-01-09
When i do a fresh install of windows onto a computer that has a 5in1/6in1 media card reader, my root windows drive always ends up with a drive letter asigned at the end of the ladder. I.E. instead of C:\ I end up with F:\ for the windows root.  Ive run in to this problem twice now. Im unable to just change it using the disk managment mmc, because its the windows drive. Ive also tried changing it (after install) in HKLM\System\MountedDevices, but that was a mistake.  What can i do to make this right?
Question by:victorjones1
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Accepted Solution

Lee W, MVP earned 500 total points
Comment Utility
Disconnect the reader until after the install
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Expert Comment

Comment Utility
re-install  start again without any usb devices plugged in. :) I know its an echo

Expert Comment

Comment Utility
The below is from Microsoft, but you are definitely taking a risk.  This is the only way I know of, maybe another expert has a less risky method.  Also, you may have to change environmental variables.

This article is for Windows 2000, but the same concepts apply to Windows XP.  NOTE: Some user's have reported that this has rendered their system unbootable. Others have reported that it works.  

If you follow this procedure, you do so at your own risk.;EN-US;Q223188

Changing the System/Boot Drive Letter

IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
256986 Description of the Microsoft Windows Registry

This article describes how to change the system or boot drive letter in Windows. For the most part, this is not recommended, especially if the drive letter is the same as when Windows was installed. The only time that you may want to do this is when the drive letters get changed without any user intervention. This may happen when you break a mirror volume or there is a drive configuration change. This should be a rare occurrence and you should change the drive letters back to match the initial installation. NOTE: Please be aware of the following issue related to drive letters:
249321 Unable to Log on if the Boot Partition Drive Letter Has Changed

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To change or swap drive letters on volumes that cannot otherwise be changed using the Disk Management snap-in, use the following steps.

NOTE: In these steps, drive D refers to the (wrong) drive letter assigned to a volume, and drive C refers to the (new) drive letter you want to change to, or to assign to the volume.

This procedure swaps drive letters for drives C and D. If you do not need to swap drive letters, simply name the \DosDevice\letter: value to any new drive letter not in use.

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Changing the System/Boot Drive Letter
Make a full system backup of the computer and system state.
Log on as an Administrator.
Start Regedt32.exe.
Go to the following registry key:

Click MountedDevices.
On the Security menu, click Permissions.
Check to make sure Administrators have full control. Change this back when you are finished with these steps.
Quit Regedt32.exe, and then start Regedit.exe.
Go to the following registry key:

Find the drive letter you want to change to (new). Look for "\DosDevices\C:".
Right-click \DosDevices\C:, and then click Rename.

NOTE: You must use Regedit instead of Regedt32 to rename this registry key.
Rename it to an unused drive letter "\DosDevices\Z:". (This will free up drive letter C: to be used later.)
Find the drive letter you want changed. Look for "\DosDevices\D:".
Right-click \DosDevices\D:, and then click Rename.
Rename it to the appropriate (new) drive letter "\DosDevices\C:".
Click the value for \DosDevices\Z:, click Rename, and then name it back to "\DosDevices\D:".
Quit Regedit, and then start Regedt32.
Change the permissions back to the previous setting for Administrators (this should probably be Read Only).
Restart the computer.
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Expert Comment

Comment Utility
That procedure will render you computer unbootable if you follow it there are alot more absolute paths in the registry that the article doesn't cover hence most of your programs wont work even if you get windows to boot.  My suggestion is to do like previously mentioned and disconnect the 6 in 1 reader until you have installed xp this will solve the problem without a hitch.

Author Comment

Comment Utility
That was my next plan..was hoping i wouldnt have to spend more time on it though. I tried that registry fix just in case last night, the systme doesnt boot as was assumed. Guess its a reinstall no matter what.

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