Troubleshooting Tools and Strategies

The Emergency Repair Process is a text-mode tool that you can use to repair or recover a system that cannot properly start. It helps you repair problems caused by damaged or deleted operating system files or a corrupted system volume boot sector.

The Emergency Repair Process can repair system files and re-enable the system to start up—it does not back up any files or programs.

The Emergency Repair Process can perform the following tasks:

  • Inspect and repair the startup environment.

  • Verify and replace system files.

  • Replace the system volume boot sector.

  • Replace the registry if it is missing or badly corrupted.



Using the Emergency Repair Process to repair registry problems is not recommended. The copy of the registry that the Emergency Repair Process restores is the original registry created during Setup. To back up the current registry in Windows 2000, you have one of two options using Backup:

  1. Perform a backup of the System State data. This backs up the registry, the Component Services class registration database, and all system startup files.

  2. Create a new ERD, and then back up the registry at the same time.

As a result of either action, the registry files are copied to the %systemroot%\Repair\RegBack folder. The registry files backed up with these processes are not the ones restored by the Emergency Repair Process. The Emergency Repair Process refers to the registry files stored in the %systemroot%\Repair folder. To use these backup registry files for system restoration, use the Recovery Console to copy the backed up registry files to the %systemroot%\System32\Config folder. For more information about restoring backed up registry files by using the Recovery Console, see Recovery Console earlier in this chapter.

To prepare for the Emergency Repair Process, create an Emergency Repair Disk (ERD).

To create an ERD

  1. From the Start menu, click Programs , Accessories , System Tools , and Backup .

  2. On the Welcome tab, click Emergency Repair Disk .

  3. Insert an empty, high-density 3.5-inch floppy disk into the floppy disk drive.

  4. When the process is complete, remove the disk, label it Emergency Repair Disk, and then store it in a safe location.



Windows 2000 does not include the Rdisk.exe program that was used in Microsoft Windows NT version 4.0 and earlier versions to create an ERD.

When the ERD is created, the files listed in Table 31.4 are copied from the %systemroot%\Repair folder to a floppy disk.

Table 31.4 Contents of the ERD

File Name



A copy of %systemroot%\Repair\Autoexec.nt, which is used to initialize the MS-DOS environment.


A copy of %systemroot%\Repair\Config.nt, which is used to initialize the MS-DOS environment.


A copy of %systemroot%\Repair\Setup.log, which lists the files installed by Setup as well as their cyclic redundancy check (CRC) data for use during the Emergency Repair Process.



The Emergency Repair Process relies on data saved in the %systemroot%\Repair folder. Do not change or delete this folder.

The registry in Windows 2000 is too large to fit on a floppy disk, and the registry entries are no longer included on the ERD.

To restore your system with the Emergency Repair Process, use the Windows 2000 operating system CD or the Windows 2000 Setup disks and the ERD. During the restore process, press F1 for more information about your options.



You must use the correct CD-ROM for repairs. You cannot use setup CDs for different languages or incorrect versions.

To restore your system with the Emergency Repair Process

  1. Use the Windows 2000 Professional operating system CD to start your computer. If you have a computer that cannot start up from a CD-ROM, use the Windows 2000 Setup disks instead.

  2. At the Setup Notification screen, press ENTER to continue.

  3. At the Welcome to Setup screen, press R to select the option to repair a Windows 2000 installation.

  4. When prompted to choose the type of repair or recovery option required, press R to repair a Windows 2000 installation by using the Emergency Repair Process.

  5. Choose the type of repair option you want to use:

    • Press M for Manual Repair.

    • Press F for Fast Repair.

  6. Follow the instructions that appear and insert the ERD when prompted. If you have the original Windows 2000 operating system CD, you can have Setup check your disk for corruption.



Because missing or corrupted files are replaced with files from the Windows 2000 operating system CD, changes made after the original installation are lost. Any Service Pack or hotfix installations must be reapplied after using the Emergency Repair Process to restore system files.

If you choose Fast Repair, all repair options are automatically performed, including examination of the registry files. If the registry files are corrupted or missing, Fast Repair automatically replaces them with the copies stored in %systemroot%\Repair.

Manual Repair allows you to select from the following three options:

Inspect Startup Environment.    Inspect Startup Environment verifies that the Windows 2000 files in the system volume are the correct ones. If any of the files that are needed to start Windows 2000 are missing or corrupted, Repair replaces them from the Windows 2000 operating system CD. If Boot.ini is missing, it is recreated.



The replacement Boot.ini only contains information for the current installation. If your system was configured as a multiple-boot system, the nondefault entries in Boot.ini are not recreated.

Verify Windows 2000 System Files.    Verify Windows 2000 System Files uses a checksum to verify that each installed file is good and that it matches the file that was installed from the Windows 2000 operating system CD. If the recovery process determines that a file on the disk does not match what was installed, it displays a message that identifies the file and asks whether you want to replace it. The Emergency Repair Process also verifies that startup files, such as Ntldr,, and Ntoskrnl.exe, are present and valid.

Inspect Boot Sector.    Inspect Boot Sector verifies that the boot sector on the system volume references Ntldr, and replaces it if it does not. The Emergency Repair Process can only replace the boot sector for the system volume on the first hard disk.

If the Emergency Repair Process was successful, your computer automatically restarts, and you likely have a working system.



Make a copy of the ERD and store it in a secure location, perhaps off-site.

There are a couple of points to consider about maintaining and using the ERD:

  • Be sure to maintain a copy of your current ERD.

  • The ERD is not a replacement for backups.

If any of the files that Windows 2000 installs on the system volume are missing or corrupted, you cannot start your computer. You can restore any of the files listed in Table 31.5 by using the ERD.

Table 31.5 Additional Files Restored by the ERD








Ntbootdd.sys (only applies to systems using SCSI disks)




For more information about creating and using the ERD, see Windows 2000 Professional Help.