Article ID: 196603 - View products that this article applies to.
This article was previously published under Q196603
The following are recommended recovery options for computers running Windows NT 4.0 with Service Pack 4 and later installed:
Uninstalling the Service PackIf an administrator can log on to the computer and run an application, uninstall the service pack by running the Add/Remove Programs tool in Control Panel, selecting Windows NT 4.0 Service Pack 4 or later, and clicking the Remove button. 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 stops responding (hangs) during startup, this is not a viable option.
Using an ERD Created After Installing the Service PackThe Windows NT 4.0 Service Pack 4 and later installation modifies the Setup.log file in the Repair directory on the system to reference the correct checksum value for the 6 files that need to match the Sam and Security registry files. This lets you run the repair procedure and repair system files and only try to repair the six files if they do not match the checksum value for the Service Pack 4 and later versions. The registry files are not updated in the Repair directory until you run the Rdisk program. The SAM and Security hives are not updated unless you run Rdisk with the /s parameter. If the Service Pack 4 and later versions of the six files are on the system but the registry files are restored from the repair information before Service Pack 4 and later are installed, the registry files will be updated on system startup.
For more information about rdisk, please see the following article in the Microsoft Knowledge Base:
156328NOTE: To use the Emergency Repair procedure, you must have the updated version of Setupdd.sys. The updated version is contained in Service Pack 2, 3, and 4 and later. 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.
(http://support.microsoft.com/kb/156328/EN-US/ )Description of Windows NT Emergency Repair Disk
For more information, please see the following article in the Microsoft Knowledge Base:
168015Repairing the Windows NT system files will replace the current files on the system with files from the Windows NT 4.0 installation media. 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 restarted. This method should only be used if the system is in an unbootable state.
(http://support.microsoft.com/kb/168015/EN-US/ )Files Not Replaced When Running Emergency Repair
If, when running the repair procedure and inspecting the System files, it prompts to repair Samsrv.dll, Samlib.dll, Winlogon.exe, Lsasrv.dll, Services.exe, or Msv1_0.dll, you can either repair them and replace with the Windows NT 4.0 media versions or choose not to repair these specific files. If you still cannot start the system, you can either replace these files manually with Service Pack 4 and later versions by starting to another installation on the computer that can access the file system of the volume containing these system files or modify the Setup.log file on the emergency repair disk to replace the files with Service Pack 4 and later revisions with the following procedure:
(http://support.microsoft.com/kb/164471/EN-US/ )Replacing System Files Using a Modified Emergency Repair Disk
"Upgrading" Windows NT 4.0 Over Windows NT 4.0 with Service PackNOTE: If you had to use Service Pack files to install originally, these files will need to be used during this upgrade procedure. For example, if you used the SP4 atapi.sys to access an ide drive larger than 8GB, follow the procedure in the following article in the Microsoft Knowledge Base:
197667If the computer is unable to start 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 4 and later. Please follow these steps to do this:
(http://support.microsoft.com/kb/197667/EN-US/ )Installing Windows NT Server on a Large IDE Hard Disk
The Setupdd.sys file is available for download from the following location: