The following are recommended recovery options for Windows NT 4.0 computers with Service Pack 3 installed:

•	Run an Emergency Repair with an Emergency Repair Disk that was created after installing Service Pack 3
•	Use the Uninstall feature available in the Update.exe in the Service Pack
•	Run an Emergency Repair with the Repair folder on the boot drive

The following methods can be modified to repair an installation:

•	Upgrade of Windows NT 4.0 over Windows NT 4.0 with Service Pack 3 installed. For example, when the system restarts after the text-mode portion of Setup is complete, choose the Upgrade option rather than the New or Repair options.
•	Emergency Repair using an Emergency Repair Disk created prior to Service Pack 3.

Due to changes in the Registry Security Hive, the Samsrv.dll, Samlib.dll, and Winlogon.exe have changed and previous versions of these files cannot access Windows NT system security information. If pre-Service Pack 3 versions of these files are present, you receive a stop screen with the stop code 0xC00000DF. (IE: The specified domain name does not exist)

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Using an ERD Created After Installing the Service Pack

Windows NT 4.0 Service Pack 3 contains a modified Setup.log file that lets you recover a Windows NT Server or Workstation installation after software failure. If the system is in an unbootable state, you must use an Emergency Repair Disk created after installing Service Pack 3 with the RDISK command. For more information, please see the following article(s) in the Microsoft Knowledge Base:

NOTE: To use the Emergency Repair Disk utility, you must have the updated version of Setupdd.sys. The updated version is contained in Service Pack 2 (as well as this Service Pack.) To update your version of Setupdd.sys, you must copy Setupdd.sys from the Service Pack to your installation disk 2. This replaces the previous version of Setupdd.sys with the updated version. For more information, please see the following article(s) in the Microsoft Knowledge Base:

Repairing the Windows NT installation using this disk recovers the system to a NO SERVICE PACK installation.

This ensures recoverability for users where the system has become unstable after the application of the Service Pack. If a Service Pack is required, it must be reapplied when the Emergency Repair is completed and the system has rebooted.

This method should only be used if the system is in an unbootable state. The following Service Pack 3 files remain after the system has been returned to a basic Windows NT 4.0 state so that Windows NT can read and utilize the new Security hives:

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Uninstalling the Service Pack

If an administrator can log onto the computer and run an application, then rerun the Service Pack Update utility and uninstall the Service Pack. This is always the preferred method of recovery. When using the uninstall feature, the computer is restored to the system configuration as it was directly before applying the Service Pack. If the computer hangs during startup, this is not a viable option.

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Repairing the System Files and the System and Security Hives

If the computer is unbootable and there is a pre-Service Pack 3 Emergency Repair Disk, you must choose to repair the system files and the System and Security hives. An alternative method is to use the Repair folder by running Emergency Repair and selecting the option for no Emergency Repair Disk. If RDISK has not been run after the application of Service Pack 3, you must choose to repair the System and Security hives or follow the procedure outlined below in order to alter the Setup.log file:

Modify the contents of the Emergency Repair Disk (ERD) by doing the following:

1.	Remove the attributes from the Setup.log file by typing the following at the command prompt: attrib -r -h -s a:\SETUP.LOG
2.	Add the following lines under the [Files.WinNt] section of the Setup.log file: \Winnt\System32\Samsrv.dll = "samsrv.dll","30fde","\","nt40 repair disk","samsrv.dll" \Winnt\System32\Samlib.dll = "samlib.dll","18010","\","nt40 repair disk","samlib.dll" \Winnt\System32\Winlogon.exe = "winlogon.exe","2d0bb","\","nt40 repair disk","winlogon.exe" NOTE: \Winnt represents the folder where Windows NT is installed.
3.	Copy Samsrv.dll, Samlib.dll, and Winlogon.exe from the Windows NT 4.0 Service Pack 3 media to the root folder of the Emergency Repair Disk.
4.	Restart your computer with the three Windows NT 4.0 Setup disks.
5.	Select "R" to Repair your Windows NT installation.
6.	Select "Verify Windows NT System Files" and continue.
7.	If prompted to insert Windows NT setup disk 4, press ESC to continue with the Repair process.
8.	After you replace Samsrv.dll, Samlib.dll, and Winlogon.exe with the files from Windows NT 4.0 Service Pack 3, press F3 to exit Repair.
9.	Reboot the computer and restart Windows NT.

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"Upgrading" Windows NT 4.0 Over Windows NT 4.0 with Service Pack

If the computer is unable to boot and the repair process fails or you do not have an Emergency Repair Disk or a CD-ROM drive, you must perform an upgrade of Windows NT 4.0 over Windows NT 4.0 Service Pack 3. Please follow these steps to do this:

1.

Copy the i386 folder from the original Windows NT 4.0 CD-ROM to the hard disk of the target system if FAT, or to a network share if NTFS. In this folder, rename the following files. Copy these same three files to the I386 directory from the Service Pack 3 source. The goal is for the upgrade to be done using these 3 files from Service Pack 3. Samsrv.dl_ to Samsrv.org Samlib.dl_ to Samlib.org Winlogon.ex_ to Winlogon.org

2.

Choose the correct procedure below based on your file system: • If the file system is FAT and the i386 folder is on the local hard disk, perform the following steps: a. Boot to MS-DOS and run WINNT /B from the i386 folder. b. Choose the Upgrade option during the on the first boot into GUI mode. • If the install source location is remote and the local file system is FAT, you must either install Windows with networking enabled, or create an installation boot disk off the Windows NT Server CD-ROM, connect to the modified i386 folder, and then run WINNT /B. • If the file system is NTFS, you must create a parallel install in a new folder and then run WINNT32 /B from the modified i386 folder.

When the Samsrv.dll, Samlib.dll, and Winlogon.exe files do not match during logon, users receive a stop screen with the stop code 0xC00000DF. This can be seen after you upgrade Windows NT 4.0 over Windows NT 4.0 Service Pack 3 or if the System and Security hives were not repaired when using an Emergency Repair Disk created prior to the application of Service Pack 3. In order to repair installations in this state, please see the following article(s) in the Microsoft Knowledge Base:

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