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Q153619: Windows NT 4.0 Configures PC-Card Hard Disk as Drive C

Article: Q153619
Product(s): Microsoft Windows NT
Version(s): 4.0
Operating System(s): 
Keyword(s): 
Last Modified: 09-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Workstation version 4.0 
- Microsoft Windows NT Server version 4.0 
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SYMPTOMS
========

If you run Windows NT on a computer with two IDE adapters (for example, Dual
channel EIDE) and a PC-Card (PCMCIA) controller with a type III slot (suitable
for hard disks), you may encounter the following problem.

When you boot Windows NT with a PC-Card hard disk, your internal fixed disk is no
longer configured as drive C. This drive letter is assigned to the PC-Card disk
instead.

Because the drive letters of your internal hard disk have changed, most of your
applications will stop working.

CAUSE
=====

When configuring the PC-Cards, Pcmcia.sys detects that there is an IDE hard disk
in the slot and tries to find an available IDE adapter configuration. If the
primary and secondary adapter are in use (for example, one disk and one CD-ROM,
each on its own bus) it will configure the PC-Card as a third adapter on IO port
0x160.

Later during the startup process, when the ATDISK driver starts up it will search
for possible IO ports, it will find the interface of the PC-Card first and
configure the PC-Card hard disk as hard disk 0.

If there is no manual drive letter configuration in the registry, hard disk 0
will be configured as drive C and the drive letters of the other volumes will be
changed.

WORKAROUND
==========

To regain your original drive letter assignment you need to create a manual
configuration for your drive letters as follows:

1. Log in with an administrative account and, using Disk Administrator,
  configure your CD-ROM drive to a high drive letter such as Z.

2. Shut down Windows NT, turn off the computer and remove the PC-Card hard disk.

3. Turn on the computer, boot Windows NT and log on as an administrator.

4. Quit all applications and stop and disable unneeded services, for example
  server service, so you have maximum number of unlocked volumes. Volumes
  containing Windows NT and a page file cannot be unlocked.

NOTE: For more information on locked volumes, please see the following article in
the Microsoft Knowledge Base:

Q136425Err Msg: The Drive Cannot Be Locked for Exclusive Use

1. Start Disk Administrator and write down the current drive letter assignments.

2. Reassign all drive letters of your hard disk to some high drive letter
  starting with the high drive letters, for example, assign F to Y, E to X and
  so on.

3. If a drive is locked you have to restart to make the change effective. On
  restart you might get a message stating that you do not have a proper page
  file. You can ignore this until you are finished with the process.

4. Continue the change as described in step 6. You may have to repeat step 4
  after the restart to unlock volumes.

5. When all drive letters are changed and there is no drive C after restart, you
  can start to move the drive letters back to their original assignment. You
  may have to restart here too because of locked volumes.

6. When all drive letters are on their original place, shut down Windows NT,
  turn off the computer, and insert the PC-Card hard disk into the slot.

7. Turn on the computer again, start Windows NT and log on as an administrator.

8. The PC-Card hard disk should use the first available drive letter. At this
  point you can take care of your page file and enable the services you
  disabled in step 4.

9. Do not forget to save the current configuration to a floppy disk in Disk
  Administrator and to run RDISK. You can use this information to import drive
  letter assignments in other Windows NT installations on this computer, for
  example if you have to reinstall for some reason.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products listed at
the beginning of this article. We are researching this problem and will post new
information here in the Microsoft Knowledge Base as it becomes available.

Additional query words: 3.51 prodnt kbbug3.51
======================================================================
Keywords          :  
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400
Version           : 4.0

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