Unable to Log on if the Boot Partition Drive Letter Has Changed

• Microsoft Windows 2000 Advanced Server
• Microsoft Windows 2000 Datacenter Server
• Microsoft Windows 2000 Professional
• Microsoft Windows 2000 Server

SYMPTOMS

After you try to log on to your Windows 2000-based computer by using a valid user name and password, the Loading your personal settings dialog box is displayed, followed by the Saving your settings dialog box. However, the desktop does not appear, and the Welcome to Windows logon screen is displayed again.

NOTE: If the paging file is located on the system or boot partition, you may also receive a warning message stating that your computer is running on limited virtual memory before returning to the Welcome to Windows logon screen.

CAUSE

This problem can occur if your Windows 2000 boot partition drive letter does not match the drive letter assigned during the initial Windows 2000 Setup. Windows 2000 maintains a record of drive letters in a registry based database and re-assigns drive letters based on Globally Unique Identifiers (GUID) recorded for each volume. Should the volume GUID change or be duplicated (by hard drive cloning software), the original drive letter may not be re-assigned to the boot volume.

This may also occur if you break a system/boot mirror, and then attempt to boot to the old shadow drive if the original primary drive is missing or inaccessible. This is because the volume GUID for the shadow drive is different than that of the original primary drive and does not get the same drive letter assigned.

RESOLUTION

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys and Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it. If you are running Windows NT, you should also update your Emergency Repair Disk (ERD).

To permit a logon and/or change the boot volume drive letter back to its originally assigned letter, use any of the following methods: NOTE: If the computer is networked but not part of a domain, you may need to map a connection to the machines IPC$ share using that computer's local administrator credentials before being able to attach using Regedit.exe or Regedt32.exe as described below to make changes.

net use \\remote_machine_name\IPC$ /user:administrator *

1. Remove any cloned hard disks added to your computer since the time the logon failures occurred, restart your computer, and then try to log on.



2. If the computer is networked, run Regedit.exe on another computer to open and modify the registry of the computer that is experiencing the logon failure. Use the information in the following Microsoft Knowledge Base article to change the drive letter back to the original letter assigned to the boot partition:

   Q223188 How to Change the System/Boot Drive Letter in Windows 2000




3. If the computer is networked, run Regedt32.exe or Regedit.exe on another computer to open and modify the registry of the computer that is experiencing the logon failure. Change the following entry to remove the full path to the Userinit.exe entry as follows:
   
   Change from:

   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\Current Version\Winlogon\Userinit:Reg_SZ:C:\WINNT\system32\userinit.exe

   Change to:

   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\Current Version\Winlogon\Userinit:Reg_SZ:userinit.exe

   After you change the preceding registry entry and are able to logon, perform the steps in the following Microsoft Knowledge Base article to re-assign the proper drive letter to your boot partition and reboot:

   Q223188 How to Change the System/Boot Drive Letter in Windows 2000




4. Create a "fake" Winnt\System32 folder structure on the drive that is suspected as being assigned the original boot partition drive letter, and then expand and copy the Userinit.exe file from the Windows 2000 CD-ROM into the Winnt\System32 folder on that drive.
   
   You can use the Recovery Console to perform this procedure provided the local security policy\security option "Recovery Console: Allow floppy copy and access to all drives and all folders" is enabled. This will permit the follwing Recovery Console command to work so you can gain unlimited access to all drives and paths: SET allowallpaths = TRUE This can be implemented as a policy on a domain controller to be applied to the local computer by using the information contained in the following Microsoft Knowledge Base article:

   Q235364 Description of the SET Command in Recovery Console

   After you perform the preceding procedure and you are able to log on, perform the steps in the following Microsoft Knowledge Base article to re-assign the proper drive letter to your boot partition and reboot:

   Q223188 How to Change the System/Boot Drive Letter in Windows 2000

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article.

MORE INFORMATION

For additional information about this issue, click the article number below to view the article in the Microsoft Knowledge Base:

Q234048 How Windows 2000 Assigns, Reserves, and Stores Drive Letters

Additional query words: reoccuring secedit

Keywords : kbenv kbtool
Version : WINDOWS:2000
Platform : WINDOWS
Issue type : kbprb